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Do you have a Gmail account? Then, you'll want to read this step by step tutorial for configuring and installing the latest version of Postfix with SASL authentication and TLS encryption necessary for connecting and relaying Gmail to smtp.gmail.com. Plus, I'll walk you through configuring fetchmail (with STARTTLS), which will grab (fetch) Gmail to your local system. But it does not stop there. You'll learn how to forward mail to other computers you have in the house, plus how to automatically backup copies of email.
Quick Background
Postfix is a mail server,or MTA (Mail Transfer Agent). It accepts messages and delivers them. In contrast, fetchmail is a remote-mail retrieval system, providing home users like you (and me), who don't have corporate accounts, the ability to pull down mail from an ISP, or in this case Gmail, to our local Linux box. All examples are done and tested with the fake domain name "squeezel", which is my 4 year olds word for the concatenation of "squeeze" and "wheezel" (weasel). You should choose a unique, fake, domain name, or one that you do not anticipate going to on the Internet.
Safety First: fetchmail with STARTTLS and sslcertck, Postfix with smtp_tls_per_site
It is very important to setup fetchmail with some type of encryption. Otherwise, your Gmail password will be broadcast over the Internet every time the fetchmail daemon tries to pickup mail, which could be every 90 seconds. Fetchmail should also perform strict certificate checking with sslcertck to prevent man-in-the-middle attacks. Likewise, Postfix should be configured with strict certificate checking with smtp_tls_per_site, before establishing an encrypted connection to smtp.gmail.com. With both fetchmail and Postfix, it is not enough to establish an encrypted connection, you must also perform strict certificate checking to prevent man-in-the-middle attacks.
Get the latest version of Postfix. As of this writing, the latest version is 2.2.10, which was released on April 4, 2006. You can find out what version you have with the following command:
$ postconf mail_version mail_version = 2.2.10
From the Postfix Home Page download the latest version.
NcFTP is a popular alternative to ftp. If you don't have it, ftp or wget will do. This example is done with postfix-2.2.10 - Again, check for updates.
$ ncftpget ftp://mirrors.loonybin.net/pub/postfix/official/postfix-2.2.10.tar.gz
$ ncftpget ftp://mirrors.loonybin.net/pub/postfix/official/postfix-2.2.10.tar.gz.sig
$ ncftpget ftp://mirrors.loonybin.net/pub/postfix/wietse.pgp
Next, import the pgp key.
$ gpg --import wietse.pgp
gpg: key C12BCD99: public key "Wietse Venema <wietse@porcupine.org>" imported
gpg: key D5327CB9: public key "wietse venema <wietse@porcupine.org>" imported
gpg: Total number processed: 2
gpg: imported: 2 (RSA: 2)
Verify that the source is valid
$ gpg --verify postfix-2.2.10.tar.gz.sig postfix-2.2.10.tar.gz
Extract the files:
$ tar -xzf postfix-2.2.10.tar.gz
Since you're connecting to Google's Gmail, you'll need to compile Postfix with TLS (for encryption) and SASL (for authentication).
2.1 First Upgrade OpenSSL and SASL
Special note: some older versions of Red Hat 8,9.0 may not have an updated version of openssl. Check to see what version you have with the following command. But, you probably do NOT want to move to the 0.9.8n versions. Instead, stick with 0.9.7i. However, the Fedora Core 5 distribution seems work fine with 0.9.8a.
$ openssl version
OpenSSL 0.9.7i 14 Oct 2005
If you need to upgrade openssl, find out where the current "openssl" directory is located. The default settings for openssl put it in "/usr/local/ssl", but Red Hat and Fedora users will find it in "/usr/share/ssl". Since my computers are Red Hat 9.0 and Fedora Core 2 and 3, I'll put the executable in "/usr/bin/openssl" and the related directories in "/usr/share/ssl". Therefore, I'll compile it with the following settings:
$ ./config --prefix=/usr --openssldir=/usr/share/ssl
$ make
$ make test
$ make install
2.2 Upgrading Cyrus SASL
You may have authentication problems without the latest upgrade. I had the following error in my "/var/log/maillog" with the default Fedora 3 install; however, the cyrus-sasl package from source fixed the problem.
Authentication failed: cannot SASL authenticate to server smtp.gmail.com[64.233.163.109]: no mechanism available
You can get the latest "cyrus-sasl" package from "http://ftp.andrew.cmu.edu/pub/cyrus-mail/". Yes, that was "http://" in front of the "ftp.andrew...". It is no longer an ftp site. Make sure you search for the latest package. As of this writing, the following is the latest.
$ wget http://ftp.andrew.cmu.edu/pub/cyrus-mail/cyrus-sasl-2.1.21.tar.gz
$ wget http://ftp.andrew.cmu.edu/pub/cyrus-mail/cyrus-sasl-2.1.21.tar.gz.sig
$ gpg --verify cyrus-sasl-2.1.21.tar.gz.sig cyrus-sasl-2.1.21.tar.gz
$ tar -xzf cyrus-sasl-2.1.21.tar.gz
$ cd cyrus-sasl-2.1.21
$ ./configure
$ make
$ make install
$ ln -s /usr/local/lib/sasl2 /usr/lib/sasl2
Again, you will probably want to upgrade these two packages, as they provide new tools for creating certificates. Also, some older versions may cause problems when Postfix is compiled, since there is an outdated "ssh.h" file.
When compiling with gcc (GCC) 4.0.1 20050727 on Fedora Core 4, you may notice the following error:
client.c:64: error: static declaration of 'global_callbacks' follows non-static declaration saslint.h:112: error: previous declaration of 'global_callbacks' was here
This can be corrected by commenting out the offending line (saslint.h, line 122). GCC 4.0.1 performs advanced checking, exposing problems like this in the source.
/* extern sasl_global_callbacks_t global_callbacks; */
2.3 Add Postfix User (postfix) and Group (postdrop)
So at this stage you've upgraded openssl and sasl, correct? If you have authentication failures, then, upgrade those packages. I had problems with Fedora Core 3 "RPM" installs, so I had to upgrade.
Next, you will add "postfix" as a user. Normally, you don't want this user to have a home directory ("-M"), or login capability ("-s /sbin/nologin"), so these two commands can be used:
# useradd -M -s /sbin/nologin postfix
# groupadd postdrop
2.4 Make Options
You do not need to add "postfix" to the group "postdrop"; it lives alone.
Now you are ready to run make. If you need to re-run make, you should issue the "make tidy" command to clean up the old files.
Choose "Option 1" if you don't have MySQL. Postfix can work with MySQL tables, so it may be something you want to try later, after you get Gmail working.
To Clean Up Everything if Needed
$ make tidy
Option 1: TLS and SASL2. You need at least this for Gmail.
$ make makefiles CCARGS="-DUSE_TLS -DUSE_SASL_AUTH -DUSE_CYRUS_SASL -I/usr/include/sasl" \
AUXLIBS="-lssl -lcrypto -lsasl2"
Option 2: TLS SASL2 and MySQL.
$ make makefiles CCARGS="-DUSE_TLS -DUSE_SASL_AUTH -DUSE_CYRUS_SASL -I/usr/include/sasl -DHAS_MYSQL -I/usr/local/include/mysql" \
AUXLIBS="-lssl -lcrypto -L/usr/local/lib/mysql -lmysqlclient -lz -lm -lsasl2"
Or, if MySQL libs are in "/usr/lib/mysql", then, something like the following.
$ make makefiles CCARGS="-DUSE_TLS -DUSE_SASL_AUTH -DUSE_CYRUS_SASL -I/usr/include/sasl -DHAS_MYSQL -I/usr/include/mysql" \
AUXLIBS="-lssl -lcrypto -L/usr/lib/mysql -lmysqlclient -lz -lm -lsasl2"
$ make
$ make install
Special Note: Reference SASL_README if you have problems running make. Option 1 worked for FC4 and FC5.
Also, the -DUSE_CYRUS_SASL option is needed to prevent the following problem: "warning: unsupported SASL server implementation: cyrus".
Reference the RELEASE_NOTES.
If you get the following error:
/usr/lib/libdb.so: undefined reference to `pthread_condattr_setpshared'
/usr/lib/libdb.so: undefined reference to `pthread_mutexattr_destroy'
/usr/lib/libdb.so: undefined reference to `pthread_mutexattr_setpshared'
/usr/lib/libdb.so: undefined reference to `pthread_mutexattr_init'
/usr/lib/libdb.so: undefined reference to `pthread_mutex_trylock'
Add -lpthread to the make configuration.
$ make makefiles CCARGS="-DUSE_TLS -DUSE_SASL_AUTH -I/usr/include/sasl" \
AUXLIBS="-lssl -lcrypto -lsasl2 -lpthread"
2.5 Install Questions
After the "make install", you will be asked questions on where to place files. Unless you need to do otherwise, take the defaults. This will make it easy to follow the directions later.
There are questions prompted when running make install
Warning: if you use this script to install Postfix locally,
this script will replace existing sendmail or Postfix programs.
Make backups if you want to be able to recover.
Before installing files, this script prompts you for some definitions.
Most definitions will be remembered, so you have to specify them
only once. All definitions should have a reasonable default value.
Please specify the prefix for installed file names. Specify this ONLY
if you are building ready-to-install packages for distribution to other
machines.
install_root: [/]
Please specify a directory for scratch files while installing Postfix. You
must have write permission in this directory.
tempdir: [/home/src/postfix/postfix-2.2.10]
Please specify the final destination directory for installed Postfix
configuration files.
config_directory: [/etc/postfix]
... [SNIP] ...
pages. You can no longer specify "no" here.
manpage_directory: [/usr/local/man]
Please specify the destination directory for the Postfix README
files. Specify "no" if you do not want to install these files.
readme_directory: [no]
2.6 What Libraries are Linked in?
Once you are done, as a check to see if ssl has been compiled into postfix, you can "ldd" the "postfix" file as follows, which will show linked libraries.
$ ldd /usr/sbin/postfix
linux-gate.so.1 => (0x00b83000)
libssl.so.6 => /lib/libssl.so.6 (0x00375000)
libcrypto.so.6 => /lib/libcrypto.so.6 (0x00190000)
libmysqlclient.so.15 => /usr/lib/mysql/libmysqlclient.so.15 (0x003bc000)
libz.so.1 => /usr/lib/libz.so.1 (0x00d03000)
libm.so.6 => /lib/libm.so.6 (0x00cd6000)
libsasl2.so.2 => /usr/lib/libsasl2.so.2 (0x00639000)
libpcre.so.0 => /lib/libpcre.so.0 (0x00756000)
libdb-4.3.so => /lib/libdb-4.3.so (0x04576000)
libnsl.so.1 => /lib/libnsl.so.1 (0x00101000)
libresolv.so.2 => /lib/libresolv.so.2 (0x00118000)
libc.so.6 => /lib/libc.so.6 (0x00ba1000)
libgssapi_krb5.so.2 => /usr/lib/libgssapi_krb5.so.2 (0x002c7000)
libkrb5.so.3 => /usr/lib/libkrb5.so.3 (0x002e8000)
libcom_err.so.2 => /lib/libcom_err.so.2 (0x0012d000)
libk5crypto.so.3 => /usr/lib/libk5crypto.so.3 (0x00169000)
libdl.so.2 => /lib/libdl.so.2 (0x00cfd000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x039c3000)
/lib/ld-linux.so.2 (0x00b84000)
libpthread.so.0 => /lib/libpthread.so.0 (0x00d5a000)
libkrb5support.so.0 => /usr/lib/libkrb5support.so.0 (0x002e2000)
The second line with "libssl.so" shows that I have "ssl", or the Secure Sockets Layer installed, which is needed for TLS. This is for encryption. By the way, if you take a look at rfc2246, you'll get a history of how TLS evolved from SSL.
Also a few lines further down note the entry "libsasl2.so.2", which is the Simple Authentication and Security Layer.
In my version, did I choose MySQL? The best way to tell is with the "postconf -m" option. But, yes, you can see "libmysqlclient", "libz" and "libm" linked in, which goes with the MySQL install.
2.7 Accessible Shared Libraries
By the way, if you get odd MySQL errors during the "make install", and your mysql libraries live in "/usr/local/lib/mysql", you may need to add an entry in your "/etc/ld.so.conf" file to include "/usr/local/lib/mysql" as follows:
$ cat /etc/ld.so.conf
...
/usr/local/lib/mysql
After adding this line, you must run the "ldconfig" command, then all those odd mysql libraries will be found. It's a good technique if you install a lot of software from source.
$ ldconfig
At this stage there are still some postfix configuration settings. We'll get back to them, but first, it makes sense to generate the certificates.
Again, before getting started, make sure you have the latest version of openssl. As of this writing, this is the latest version. See the steps above if you decide to upgrade. But, it's strongly suggested that you stay with the 0.9.7 line at this time, unless your distribution has moved 0.9.8. For example, Fedora Core 5 uses (OpenSSL 0.9.8a 11 Oct 2005), which seems to work fine.
$ openssl version
OpenSSL 0.9.7i 14 Oct 2005
3.1 Creating Your Own CA
You can get signed certificates from Thawte and VeriSign, but you don't have to for your home system. Instead, you will become your own "Cerificate Authority", and sign your own SSL certs.
Below is the command to create your own CA. Hit return for the first prompt to create the CA. It will then prompt you for a password, and prompt to confirm. Remember the password. Also, it's important that the "Organization Name" matches when you create the "server" certificate. I show my answers in bold, so you can see how they will match when creating and signing certificates.
$ /usr/local/ssl/misc/CA.pl -newca
CA certificate filename (or enter to create)
Making CA certificate ...
Generating a 1024 bit RSA private key
.......++++++
...................++++++
writing new private key to './demoCA/private/cakey.pem'
Enter PEM pass phrase: password123
Verifying - Enter PEM pass phrase: password123
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [US]:US
State or Province Name (full name) [Pennsylvania]:Pennsylvania
Locality Name (eg, city) []:Elkins Park
Organization Name (eg, company) []:Chirico_Widgets
...
If, after doing the above command, you find that you want to extend the key (say you didn't change the "default_days = 3650", or you did and want to change it back), you can issue the following commands:
$ openssl x509 -in demoCA/cacert.pem -days 1024 -out cacert.pem -signkey demoCA/private/cakey.pem
$ cp cacert.pem demoCA
Or, you could hard code values in "/usr/openssl.cnf", if you find that you're doing this over and over for testing. However, as you can see from the above command, it is easy enough to change the values.
3.2 Generate the Server Certificate
This is the server cert request that will be signed by the CA Authority. Note, below that the "-nodes" option is used so that the certificate will not require a pass phrase each time the secure daemon is started. I have also added my fake domain name "squeezel.squeezel.com".
$ openssl req -new -nodes \
-subj '/CN=squeezel.squeezel.com/O=Chirico_Widgets/C=US/ST=Pennsylvania/L=Elkins Park/emailAddress=mchirico@comcast.net' \
-keyout FOO-key.pem -out FOO-req.pem -days 3650
Note above that "/0=Chirico_Widgets" must match the name given in the the origional CA. For example, "/0=Widgets co." will not work. It must be exact.
3.3 Sign the Server Certificate
The following steps will sign the certificate.
$ openssl ca -out FOO-cert.pem -infiles FOO-req.pem
3.4 Copy Signed Certificates to /etc/postfix/certs
The next step copies over all the required certificates to where Postfix can find them. In addition, the correct rights are enforced on each file.
$ cp demoCA/cacert.pem FOO-key.pem FOO-cert.pem /etc/postfix $ chmod 644 /etc/postfix/FOO-cert.pem /etc/postfix/cacert.pem $ chmod 400 /etc/postfix/FOO-key.pem
If you need to generate additional certificates, say you have several servers, this is described in (section 4.12.2).
The file "/etc/postfix/main.cf" and "/etc/postfix/master.cf" are the two basic Postfix configuration files.
Postfix configuration is particular to the hostname of your computer. You can have a fake hostname, like "squeezel.squeezel.com". Pick a name and set it up as follows. (You can actually use "squeezel.squeezel.com" if you want, since it's not a real domain name, though you might want to use something more descriptive. The point is that it doesn't have to be registered to you, but does have to be unique.)
4.1 Configure the Hostname
The computer that these examples are taken from is "squeezel.squeezel.com", and it exists on IP address 192.168.1.81. The short name is just squeezel. Another computer, on IP address "192.168.1.155" is "tape.squeezel.com".
/etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
192.168.1.81 squeezel.squeezel.com squeezel
192.168.1.155 tape.squeezel.com tape
You may also want to edit "/etc/sysconfig/network" and add or check the following.
HOSTNAME=squeezel.squeezel.com
Finally, to put all changes into effect now, run the following command with root privileges.
$ hostname squeezel.squeezel.com
Some of the settings in the postfix "main.cf" file depend upon the hostname.
4.2 main.cf
The following settings can be added to the end of the "/etc/postfix/main.cf" file. Postfix reads this file from top to bottom, taking the last values assigned in this file.
## Add these lines to the bottom on main.cf
##
##
## TLS Settings
#
# For no logs set = 0
smtp_tls_loglevel = 1
#
# smtp_enforce_tls = yes
# Above is commented because doing it site by site below
smtp_tls_per_site = hash:/etc/postfix/tls_per_site
#
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_tls_cert_file = /etc/postfix/FOO-cert.pem
smtp_tls_key_file = /etc/postfix/FOO-key.pem
smtp_tls_session_cache_database = btree:/var/run/smtp_tls_session_cache
smtp_use_tls = yes
smtpd_tls_CAfile = /etc/postfix/cacert.pem
smtpd_tls_cert_file = /etc/postfix/FOO-cert.pem
smtpd_tls_key_file = /etc/postfix/FOO-key.pem
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:/var/run/smtpd_tls_session_cache
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
## SASL Settings
# This is going in to THIS server
smtpd_sasl_auth_enable = no
# We need this
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtpd_sasl_local_domain = $myhostname
smtp_sasl_security_options = noanonymous
#smtp_sasl_security_options =
smtp_sasl_tls_security_options = noanonymous
smtpd_sasl_application_name = smtpd
## Gmail Relay
relayhost = [smtp.gmail.com]:587
## Good for Testing
# sender_bcc_maps = hash:/etc/postfix/bcc_table
# Disable DNS Lookups
disable_dns_lookups = yes
#
# Great New feature Address Mapping
# for example may mchirico@localhost to mchirico@gmail.com
smtp_generic_maps = hash:/etc/postfix/generic
#
#
transport_maps = hash:/etc/postfix/transport
The TLS settings are pretty standard, and the above code is taken from the documentation, which is worth a read. Note the "*.pem" files would appear to be listed twice; however, notice the difference between "smtp" and "smtpd". One is for client connectivity and the other is for connecting to this server.
4.3 sasl_passwd
In the above "main.cf" file, there are several hashed files, or Berkeley DB files which will have to be created. Look again at the recommended entries in "main.cf", and you will notice "hash:" in front of these values. For example "hash:/etc/postfix/sasl_passwd".
Below is a sample sasl_passwd file. This will login to smtp.gmail.com with username mchirico, using the password pa33w0r8. As of Aug 2008, I noticed that gmail is only accepting connections on port 587. For further information on this setting reference SOHO_README.
# Contents of sasl_passwd
#
[smtp.gmail.com]:587 mchirico@gmail.com:pa33w0r8
Next, this file must be converted to hash format, with the following command.
$ postmap /etc/postfix/sasl_passwd
The "postmap" command must be run anytime "sasl_passwd" is changed, because this creates the "sasl_passwd.db" that postfix reads.
After you have done the above command, run this simple "hash" key test.
$ postmap -q [smtp.gmail.com]:587 sasl_passwd
mchirico@gmail.com:pa33w0r8
You'll need to protect your password so that only the postfix group and root can read it by changing the access rights as follows:
$ chown root.postfix sasl_passwd*
$ chmod 0640 sasl_passwd*
4.4 generic
The file "/etc/postfix/generic" contains the following entries. Again, my account on squeezel.squeezel.com is chirico, but the gmail account is mchirico.
chirico@squeezel.squeezel.com mchirico@gmail.com
Don't forget to run postmap on this file.
$ postmap /etc/postfix/generic
4.5 transport
# Contents of /etc/postfix/transport
#
# This sends mail to Gmail
gmail.com smtp:[smtp.gmail.com]:587
#
# Except mail going to the tape and closet server
tape.squeezel.com relay:[tape.squeezel.com]
closet.squeezel.com relay:[closet.squeezel.com]
The transport file sends all email to Gmail or "smtp.gmail.com", except for internal mail on my network, which is relayed to the appropriate servers. Sending email to "root@tape" does not send it out to the Google's smtp. Note that the return address is "chirico@squeezel.squeezel.com" because of the following entry in master.cf (see section 4.7).
4.6 smtp_tls_per_site
You want certificate verification for "smtp.gmail.com" before giving out your password. You want to make sure you're setting up an encrypted connection with the real "smtp.gmail.com". This protects you from man-in-the-middle attacks. Below, note only "closet" and "tape" must have valid certificates. If they do not have valid certificates, mail will not get delivered; it will be deferred. However, mail will be delivered to "livingroom.squeezel.com" without a valid certificate.
# Contents of /etc/postfix/tls_per_site
# After changes run:
# postmap /etc/postfix/tls_per_site
smtp.gmail.com MUST
closet.squeezel.com MUST
tape.squeezel.com MUST
livingroom.squeezel.com MAY
4.7 master.cf
This file musted by owned by root. Whenever changes are made to this file, postfix should be reloaded with "postfix reload" command.
smtp unix - - n - - smtp
relay unix - - n - - smtp
-o smtp_generic_maps=
Note the empty "smtp_generic_maps=" with nothing after the equals sign. This means anything relayed, anything going to "tape.squeezel.com" or "closet.squeezel.com" will not have an address translation. Only email going out to Gmail. What about mail from "squeezel.squeezel.com" to itself? No address translation either, which is a feature of "smtp_generic_maps".
4.8 Postfix setup - utilizing "postconf -n"
To see if all the change went into effect, here is the output of the "postconf -n" command.
[root@squeezel ~]# postconf -n
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
debug_peer_level = 2
disable_dns_lookups = yes
html_directory = no
mail_owner = postfix
mailq_path = /usr/bin/mailq
manpage_directory = /usr/local/man
newaliases_path = /usr/bin/newaliases
queue_directory = /var/spool/postfix
readme_directory = no
relayhost = [smtp.gmail.com]:587
sample_directory = /etc/postfix
sendmail_path = /usr/sbin/sendmail
setgid_group = postdrop
smtp_generic_maps = hash:/etc/postfix/generic
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_sasl_tls_security_options = noanonymous
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_tls_cert_file = /etc/postfix/FOO-cert.pem
smtp_tls_key_file = /etc/postfix/FOO-key.pem
smtp_tls_loglevel = 1
smtp_tls_per_site = hash:/etc/postfix/tls_per_site
smtp_tls_session_cache_database = btree:/var/run/smtp_tls_session_cache
smtp_use_tls = yes
smtpd_enforce_tls = no
smtpd_sasl_application_name = smtpd
smtpd_sasl_auth_enable = no
smtpd_sasl_local_domain = $myhostname
smtpd_tls_CAfile = /etc/postfix/cacert.pem
smtpd_tls_ask_ccert = yes
smtpd_tls_cert_file = /etc/postfix/FOO-cert.pem
smtpd_tls_key_file = /etc/postfix/FOO-key.pem
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:/var/run/smtpd_tls_session_cache
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
transport_maps = hash:/etc/postfix/transport
unknown_local_recipient_reject_code = 550
4.9 Starting Postfix, and Common Postfix Commands
A this point start postfix.
$ postfix start
You want postfix to start automatically for run levels 3 and 5. I have the following postfix file in "/etc/init.d". Download and copy this file using the steps below.
$ cd /etc/init.d $ wget http://sourceforge.net/direct-dl/mchirico/souptonuts/postfix $ chmod 0755 postfix $ ln -s /etc/init.d/postfix /etc/rc3.d/S80postfix $ ln -s /etc/init.d/postfix /etc/rc3.d/K80postfix $ ln -s /etc/init.d/postfix /etc/rc5.d/S80postfix $ ln -s /etc/init.d/postfix /etc/rc5.d/K80postfix
4.10 Common Postfix Commands
Below are some common postfix commands
$ /etc/init.d/postfix restart # restarts postfix needed for inet_interfaces changes
$ postfix reload # reloads most changes in main.cf
$ postfix check # checks postfix configuration
$ postconf -n # dumps setting that went into effect
$ postconf -m # shows the map types: mysql, hash, regexp ...
$ postmap <filename> # creates a map file for transports, sender_canonical etc.
$ postqueue -p # checks the queue
$ postsuper -d ALL # deletes all messages in the queue
$ postsuper -d AC8231EDA2D # deletes message AC8231EDA2D
$ postconf mail_version # this tells you what version of Postfix you are using
4.11 MySQL
Instead of using the hash type, you can leverage MySQL. Below is a sample "smtp_generic_maps" configuration for converting addresses. The text below is the "/etc/postfix/generic_mysql" file. Note, that is contains the MySQL username, password for MySQL, and the database "dbname" in this file. The comments show how this table was created in MySQL.
# The entry in main.cf is
# smtp_generic_maps = mysql:/etc/postfix/generic_mysql
#
# This is the MySQL table definition
# create table smtpg_maps (
# pkey int NOT NULL auto_increment,
# address varchar(50),
# smtp_address varchar(50),
# timeEnter timestamp(14),
# PRIMARY KEY (pkey));
#
# insert into smtpg_maps (address,smtp_address) values ('chirico@squeezel.squeezel.com','mchirico@gmail.com');
# insert into smtpg_maps (address,smtp_address) values ('lpayne@squeezel.squeezel.com','payne.lisa@gmail.com');
# insert into smtpg_maps (address,smtp_address) values ('root@squeezel.squeezel.com','mike.chirico@gmail.com');
#
# Test this with
# $ postmap -q "root@squeezel.squeezel.com" mysql:/etc/postfix/generic_mysql
#
hosts = localhost
user = mysqlmail
password = S0m3paSSw0r9
dbname = mail
query = SELECT smtp_address FROM smtpg_maps WHERE address = '%s'
4.12 Additional Items
If you are using Fedora Core, which defaults to sendmail, you may need to make a few configuration changes. For example, you may be picking up the incorrect version of sendmail.
$ alternatives --config mta
There are 2 programs which provide 'mta'.
Selection Command
-----------------------------------------------
*+ 1 /usr/sbin/sendmail.sendmail
2 /usr/sbin/sendmail.postfix
Enter to keep the current selection[+], or type selection number:
Above you will want to select 2. If you now do an "ls" on sendmail, you will now see the following results.
$ ls -l /usr/sbin/sendmail
lrwxrwxrwx 1 root root 21 Jan 13 20:53 /usr/sbin/sendmail -> /etc/alternatives/mta
$ ls -l /etc/alternatives/mta
lrwxrwxrwx 1 root root 26 Apr 28 10:34 /etc/alternatives/mta -> /usr/sbin/sendmail.postfix
$ ls -l /usr/sbin/sendmail
lrwxrwxrwx 1 root root 21 Jan 13 20:53 /usr/sbin/sendmail -> /etc/alternatives/mta
[root@squeezel ~]# ls -l /etc/alternatives/mta
lrwxrwxrwx 1 root root 26 Apr 28 10:23 /etc/alternatives/mta -> /usr/sbin/sendmail.postfix
Now try sending email. The "correct" sendmail will build a report that you can view with mutt or you email package. Below is an example test.
$ sendmail -bv zmchirico@yahoo.com
4.12.1 Backups with bcc
Any mail sent out from "gmchirico@squeezel.squeezel.com" can be blind copied to another server. In this case the server is "chirico@tape".
Contents in /etc/postfix/main.cf
sender_bcc_maps = hash:/etc/postfix/bcc_table
Remember to "postmap bcc_table" after editing the bcc_table file.
Contents of /etc/postfix/bcc_table
gmchirico@squeezel.squeezel.com chirico@tape
If you want to get copies of everything coming in and going out, then, use the "always_bcc" option. I normally create a special user for this "allmail", that way I can go forward email easily, if needed.
Setting in /etc/postfix/main.cf
always_bcc = allmail
It's not completely a blind copy, since it will show up when users on the system do a "sendmail -bv" test. Also note, there is a limit on the size file /var/spool/mail/allmail which is set by default as "mailbox_size_limit = 51200000", or 51 Megs. You can increase this option in "main.cf" or turn is off by setting this parameter to zero.
4.12.2 Generating Additional Server Certificates (closet.squeezel.com, livingroom.squeezel.com)
The following commands will generate and sign, with the CA, additional certificates for my servers "closet.squeezel.com", and "livingroom.squeezel.com". You must "cd" to the directly that contains "demoCA". Note below, only /CN=livingroom.squeezel.com changes. All other options must match. All of these commands are executed on "squeezel.squeezel.com", since it contains the CA.
$ openssl req -new -nodes \
-subj '/CN=livingroom.squeezel.com/O=Chirico_Widgets/C=US/ST=Pennsylvania/L=Elkins Park/emailAddress=mchirico@comcast.net' \
-keyout living_FOO-key.pem -out living_FOO-req.pem -days 3650
Now, sign the certificate.
$ openssl ca -out living_FOO-cert.pem -infiles living_FOO-req.pem
openssl ca -out living_FOO-cert.pem -infiles living_FOO-req.pem
Using configuration from /usr/openssl.cnf
Enter pass phrase for ./demoCA/private/cakey.pem:password123
DEBUG[load_index]: unique_subject = "yes"
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number:
90:95:88:9c:58:ff:91:0e
Validity
Not Before: Jun 5 20:15:20 2005 GMT
Not After : Jun 5 20:15:20 2006 GMT
Subject:
countryName = US
stateOrProvinceName = Pennsylvania
organizationName = Chirico_Widgets
commonName = livingroom.squeezel.com
emailAddress = mchirico@comcast.net
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
Netscape Comment:
OpenSSL Generated Certificate
X509v3 Subject Key Identifier:
FB:E5:1A:FC:05:F8:83:44:EB:CC:F8:59:F2:A3:47:A8:90:E5:5D:28
X509v3 Authority Key Identifier:
keyid:EA:DC:CD:A1:7F:78:F9:9E:43:B9:CF:01:04:BB:98:4D:19:51:46:93
DirName:/C=US/ST=Pennsylvania/L=Elkins Park/O=Chirico_Widgets/OU=Development/CN=squeezel.squeezel.com/emailAddress=mchirico@comcast.net
serial:90:95:88:9C:58:FF:91:09
Certificate is to be certified until Jun 5 20:15:20 2006 GMT (365 days)
Sign the certificate? [y/n]:y
y
1 out of 1 certificate requests certified, commit? [y/n]y
y
Write out database with 1 new entries
Data Base Updated
Similiar steps would be performed when creating a certificate for the computer "closet.squeezel.com". Note, only the /CN changes "closet.squeezel.com".
$ openssl req -new -nodes \
-subj '/CN=closet.squeezel.com/O=Chirico_Widgets/C=US/ST=Pennsylvania/L=Elkins Park/emailAddress=mchirico@comcast.net' \
-keyout closet_FOO-key.pem -out closet_FOO-req.pem -days 3650
The closet certificate is signed.
$ openssl ca -out closet_FOO-cert.pem -infiles closet_FOO-req.pem
Since creating the server certificates above are done on "squeezel.squeezel.com" the appropriate files will have to be copied. The steps below copy the needed certificates to "closet.squeezel.com".
$ scp closet_FOO-cert.pem root@closet:/etc/postfix/.
$ scp closet_FOO-key.pem root@closet:/etc/postfix/.
$ scp demoCA/cacert.pem root@closet:/etc/postfix/.
$ ssh root@closet 'chmod 644 /etc/postfix/closet_FOO-cert.pem /etc/postfix/cacert.pem'
$ ssh root@closet 'chmod 400 /etc/postfix/closet_FOO-key.pem'
$ ssh root@closet 'chown root.root /etc/postfix/*.pem'
On "closet.squeezel.com" the file "main.cf" entries should reference the needed certificates as follows:
# Part of main.cf on closet.squeezel.com
## TLS Settings
#
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_tls_cert_file = /etc/postfix/closet_FOO-cert.pem
smtp_tls_key_file = /etc/postfix/closet_FOO-key.pem
smtp_tls_session_cache_database = btree:/var/run/smtp_tls_session_cache
smtp_use_tls = yes
smtpd_tls_CAfile = /etc/postfix/cacert.pem
smtpd_tls_cert_file = /etc/postfix/closet_FOO-cert.pem
smtpd_tls_key_file = /etc/postfix/closet_FOO-key.pem
smtpd_tls_received_header = yes
smtpd_tls_session_cache_database = btree:/var/run/smtpd_tls_session_cache
smtpd_use_tls = yes
tls_random_source = dev:/dev/urandom
4.12.3 Logging TLS
If you look at the results from postconf -n, I have the following in "main.cf".
smtp_tls_loglevel = 1
Setting this to a higher number, increases the logging for each message sent. Zero turns off logging. Below is a sample log message that indicates everything is working. Note the verified Thawte certificate.
Jun 8 09:33:47 squeezel postfix/smtp[548]: setting up TLS connection to smtp.gmail.com Jun 8 09:33:47 squeezel postfix/smtp[548]: Verified: subject_CN=smtp.gmail.com, issuer=Thawte Server CA Jun 8 09:33:47 squeezel postfix/smtp[548]: TLS connection established to smtp.gmail.com: TLSv1 with cipher DES-CBC3-SH\A (168/168 bits)
4.12.4 prng_exch
By default, "prng_exch" is stored in "/etc/postfix" and caches the seed for the pseudo random number generator. For users running the tripwire feature in cfengine, (Reference TIP 165 and TIP 166) in Linux Tips you may notice that this file changes. This is normal and good. However, if this bothers you, the location can be changed. By default it is set to the following:
tls_random_exchange_name = ${config_directory}/prng_exch
4.12.5 Common Error
Test the address routing with the following command. Normally, a report is emailed verifying delivery. However, if you get the "public/pickup" error shown below, then, postfix isn't running.
$ sendmail -bv mchirico@users.sourceforge.net
postfix/postdrop[5371]: warning: unable to look up public/pickup: No such file or directory
Check the mail logs "/var/log/maillog". Also make sure another no other program is running on port 25. Perhaps sendmail is running on port 25? Is there a "/etc/init.d/sendmail" file?
Why Fetchmail?
Fetchmail pulls the email down from Google's Gmail, since for a home user with a fake domain and changing IP address their email server will not forward the email.
5. Safety First: Configure fetchmail with STARTTLS
Again, it is very important to setup fetchmail with some type of encryption. STARTTLS encryption works well, since you have already installed the necessary openssl files. You just need to pickup the necessary keys, and put them in the proper format.
5.1 Google Gmail Certificates
$ openssl s_client -connect pop.gmail.com:995 -showcerts
The command above will return the certificate from Google's Gmail as follows:
CONNECTED(00000003)
depth=0 /C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 /C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
verify error:num=27:certificate not trusted
verify return:1
depth=0 /C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
verify error:num=21:unable to verify the first certificate
verify return:1
---
Certificate chain
0 s:/C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
i:/C=US/O=Equifax/OU=Equifax Secure Certificate Authority
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
---
Server certificate
subject=/C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
issuer=/C=US/O=Equifax/OU=Equifax Secure Certificate Authority
---
No client certificate CA names sent
---
SSL handshake has read 891 bytes and written 338 bytes
---
New, TLSv1/SSLv3, Cipher is DES-CBC3-SHA
Server public key is 1024 bit
SSL-Session:
Protocol : TLSv1
Cipher : DES-CBC3-SHA
Session-ID: 923A27BC992B3D88466B65C3F2F94C70B3F481496C5FB1FF194D11E2C8E29420
Session-ID-ctx:
Master-Key: 83BFD67993E2F74AD7726DCEFE96C4EC9A0DD05FA3594817B8D8B3D123021A54CC30EEA76FEB76FED93DFA56CC203134
Key-Arg : None
Start Time: 1141583185
Timeout : 300 (sec)
Verify return code: 21 (unable to verify the first certificate)
---
+OK Gpop ready. i17pf3432638wxd
5.2 Extract Certificate
Next, you need to copy the certificate part, which is everything between the "BEGIN CERTIFICATE" part and "END CERTIFICATE" part, and save this to a file.
-----BEGIN CERTIFICATE-----
MIIC3TCCAkagAwIBAgIDBZIAMA0GCSqGSIb3DQEBBQUAME4xCzAJBgNVBAYTAlVT
MRAwDgYDVQQKEwdFcXVpZmF4MS0wKwYDVQQLEyRFcXVpZmF4IFNlY3VyZSBDZXJ0
...
-----BEGIN CERTIFICATE-----
However, notice above that the CA for this certificate is Equifax, which means you need that certificate as well. This is a very common certificate. Normally you can cut and paste them from "/usr/share/ssl/cert.pem".
If you look closely at that file you'll see the certificate. Or, you can copy it from below.
5.3 Certificate of the CA - Equifax
Equifax Secure CA ================= MD5 Fingerprint: 67:CB:9D:C0:13:24:8A:82:9B:B2:17:1E:D1:1B:EC:D4 PEM Data: -----BEGIN CERTIFICATE----- MIIDIDCCAomgAwIBAgIENd70zzANBgkqhkiG9w0BAQUFADBOMQswCQYDVQQGEwJV UzEQMA4GA1UEChMHRXF1aWZheDEtMCsGA1UECxMkRXF1aWZheCBTZWN1cmUgQ2Vy dGlmaWNhdGUgQXV0aG9yaXR5MB4XDTk4MDgyMjE2NDE1MVoXDTE4MDgyMjE2NDE1 MVowTjELMAkGA1UEBhMCVVMxEDAOBgNVBAoTB0VxdWlmYXgxLTArBgNVBAsTJEVx dWlmYXggU2VjdXJlIENlcnRpZmljYXRlIEF1dGhvcml0eTCBnzANBgkqhkiG9w0B AQEFAAOBjQAwgYkCgYEAwV2xWGcIYu6gmi0fCG2RFGiYCh7+2gRvE4RiIcPRfM6f BeC4AfBONOziipUEZKzxa1NfBbPLZ4C/QgKO/t0BCezhABRP/PvwDN1Dulsr4R+A cJkVV5MW8Q+XarfCaCMczE1ZMKxRHjuvK9buY0V7xdlfUNLjUA86iOe/FP3gx7kC AwEAAaOCAQkwggEFMHAGA1UdHwRpMGcwZaBjoGGkXzBdMQswCQYDVQQGEwJVUzEQ MA4GA1UEChMHRXF1aWZheDEtMCsGA1UECxMkRXF1aWZheCBTZWN1cmUgQ2VydGlm aWNhdGUgQXV0aG9yaXR5MQ0wCwYDVQQDEwRDUkwxMBoGA1UdEAQTMBGBDzIwMTgw ODIyMTY0MTUxWjALBgNVHQ8EBAMCAQYwHwYDVR0jBBgwFoAUSOZo+SvSspXXR9gj IBBPM5iQn9QwHQYDVR0OBBYEFEjmaPkr0rKV10fYIyAQTzOYkJ/UMAwGA1UdEwQF MAMBAf8wGgYJKoZIhvZ9B0EABA0wCxsFVjMuMGMDAgbAMA0GCSqGSIb3DQEBBQUA A4GBAFjOKer89961zgK5F7WF0bnj4JXMJTENAKaSbn+2kmOeUJXRmm/kEd5jhW6Y 7qj/WsjTVbJmcVfewCHrPSqnI0kBBIZCe/zuf6IWUrVnZ9NA2zsmWLIodz2uFHdh 1voqZiegDfqnc1zqcPGUIWVEX/r87yloqaKHee9570+sB3c4 -----END CERTIFICATE-----
To recap you should have the two certificates saved to separate files. In my case I've labeled them googlepop.pem and equifax.pem
5.4 Rehash or Creating Symlinks
Once you have created these files, you will need to run the "c_rehash" command to create the necessary sym-links. I've copied the files in "/home/chirico/certs/.certs". Then, shown below the running the "c_rehash" command.
[chirico@squeezel certs]$ c_rehash .certs
Doing .certs
googlepop.pem => 34ceaf75.0
thawte.pem => ddc328ff.0
5.5 Checking the Certificate
It's possible to check the certificates as with the "openssl s_client" command as follows:
$ openssl s_client -connect pop.gmail.com:995 -CApath /home/chirico/certs/.certs/
CONNECTED(00000003)
depth=1 /C=US/O=Equifax/OU=Equifax Secure Certificate Authority
verify return:1
depth=0 /C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
verify return:1
---
Certificate chain
0 s:/C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
i:/C=US/O=Equifax/OU=Equifax Secure Certificate Authority
---
Server certificate
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
subject=/C=US/ST=California/L=Mountain View/O=Google Inc./CN=pop.gmail.com
issuer=/C=US/O=Equifax/OU=Equifax Secure Certificate Authority
---
No client certificate CA names sent
---
SSL handshake has read 891 bytes and written 338 bytes
---
New, TLSv1/SSLv3, Cipher is DES-CBC3-SHA
Server public key is 1024 bit
SSL-Session:
Protocol : TLSv1
Cipher : DES-CBC3-SHA
Session-ID: D2A04F4F4AF96B0E7A3AF19408DA101041DE391552A0F39E14FEDB5863A49274
Session-ID-ctx:
Master-Key: 9BBCB461B2B753FC8B5EF68B5C6F3E5BDF8CF25988ECE1445D61CD71B9EEBAD9DC046159DA7289A065022E19F6B46898
Key-Arg : None
Start Time: 1134602638
Timeout : 300 (sec)
Verify return code: 0 (ok)
---
+OK Gpop h7pf1040470wxd ready.
As you can see above, the "verify return code: 0 (ok)" indicates the certificate was verified. If instead, you get the following: "Verify return code: 21 (unable to verify the first certificate)". Then, the certificate has not been verified.
5.6 The Fetchmail config .fetchmailrc
Note that the fetchmail option sslcertck, seen below in the ".fetchmailrc" file, causes fetchmail to strictly check the server certificate against a set of local trusted certificates.
Below is a sample ".fetchmailrc" file, the file that should be stored in your home directory.
#
#
# Sample /home/chirico/.fetchmailrc file for Gmail
#
# Check mail every 90 seconds
set daemon 90
set syslog
set postmaster chirico
#set bouncemail
#
# Google Gmail is mchirico but on computer it is chirico
# To keep mail on the server use the you would put keep at the end.
# user 'mchirico@gmail.com' with pass "pa33w0r8" is 'chirico' here options ssl sslcertck sslcertpath '/home/chirico/certs/.certs' keep
#
poll pop.gmail.com with proto POP3 and options no dns
user 'mchirico@gmail.com' with pass "pa33w0r8" is 'chirico' here options ssl sslcertck sslcertpath '/home/chirico/certs/.certs'
smtphost localhost
# You would use this to by-pass Postfix
# mda '/usr/bin/procmail -d %T'
These are some common fetchmail command. Normally you would want to start fetchmail with the "-v" option, and take a look at the "/var/log/maillog" files for any problems.
Quick note: smtphost localhost in ".fetchmailrc" tells fetchmail to deliver the email to the local smtp server, which is your postfix server. Make sure smtpd_enforce_tls is left unset, or is set to no, in the "/etc/postfix/main.cf" file. Otherwise, you may see the following error in "/var/log/maillog" when fetchmail is started with the "-v" option.
# Sample error message in /var/log/maillog caused when smtpd_enforce_tls is
# set to yes in the Postfix main.cf and smtphost localhost option
# is used to .fetchmailrc.
#
# smtpd_enforce_tls should be left unset or set to no in Postfix's
# main.cf
#
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP< 530 Must issue a STARTTLS command first
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP error: 530 Must issue a STARTTLS command first
Jun 9 16:40:45 squeezel postfix/smtpd[12756]: connect from localhost.localdomain[127.0.0.1]
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP< 220 squeezel.squeezel.com ESMTP Postfix
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP> HELO localhost
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP< 250 squeezel.squeezel.com
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP> MAIL FROM:<FETCHMAIL-DAEMON@squeezel.squeezel.com>
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP< 530 Must issue a STARTTLS command first
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP> QUIT
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP< 221 Bye
Jun 9 16:40:45 squeezel postfix/smtpd[12756]: disconnect from localhost.localdomain[127.0.0.1]
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP> RSET
Jun 9 16:40:45 squeezel fetchmail[11995]: SMTP< 530 Must issue a STARTTLS command first
5.7 Fetchmail Commands
Below are some of the more common fetchmail commands.
$ fetchmail -q # quits fetchmail daemon
$ fetchmail -v # start fetchmail daemon in verbose mode
$ fetchmail -c # checks for email only
$ fetchmail -S localhost # delivers mail to you Postfix server
You can simulate a TLS mail client session with the openssl. A successful session is shown below using this command. This assumes that "/usr/share/ssl/certs/" contains certificates. One note, I had some trouble using this command with openssl version 0.9.8a (unknown protocol:s23_clnt.c), so I went back to version 0.9.7i.
$ openssl s_client -starttls smtp -CApath /usr/share/ssl/certs/ -connect smtp.gmail.com:25
CONNECTED(00000003)
---
Certificate chain
0 s:/C=US/ST=California/L=Mountain View/O=Google Inc/CN=smtp.gmail.com
i:/C=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Premium Server CA/emailAddress=premium-server@thawte.com
---
Server certificate
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
subject=/C=US/ST=California/L=Mountain View/O=Google Inc/CN=smtp.gmail.com
issuer=/C=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Premium Server CA/emailAddress=premium-server@thawte.com
---
No client certificate CA names sent
---
SSL handshake has read 1187 bytes and written 369 bytes
---
New, TLSv1/SSLv3, Cipher is DES-CBC3-SHA
Server public key is 1024 bit
SSL-Session:
Protocol : TLSv1
Cipher : DES-CBC3-SHA
Session-ID: DBA9FEE390894FB77566EE9975F8DE14252F8A82007F8367E0999BFBDEF91893
Session-ID-ctx:
Master-Key: C717F8B7598CC115180E94B17552908944F734879A09664B6E0C56D12EC730B69FF3F204446961417FBEB21EBE8A7692
Key-Arg : None
Start Time: 1130720225
Timeout : 300 (sec)
Verify return code: 0 (ok)
---
depth=1 /C=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Premium Server CA/emailAddress=premium-server@thawte.com
verify return:1
depth=0 /C=US/ST=California/L=Mountain View/O=Google Inc/CN=smtp.gmail.com
verify return:1
250-mx.gmail.com at your service
250-SIZE 20971520
250-8BITMIME
250-STARTTLS
250 ENHANCEDSTATUSCODES
Also, take a look at saslfinger-1.0.tar.gz.
Postfix 2nd Instance for Sender-based Routing: Multiple Gmail and Comcast Accounts. Configure your home system to support several Gmail accounts, and additionally, Comcast and or other ISP accounts that require individual authentication rules based on the sending address. This tutorial walks you through configuring a second instance of Postfix, on a second IP address (same NIC), with sender based routing.
Linux System Admin Tips: There are over 200 Linux tips and tricks in this article. That is over 150 pages covering topics from setting and keeping the correct time on your computer, permanently deleting documents with shred, making files "immutable" so that root cannot change or delete, setting up more than one IP address on a single NIC, monitering users and processes, setting log rotate to monthly with 12 months of backups in compressed format, creating passwords for Apache using the htpasswd command, common Perl commands, using cfengine, adding users to groups, finding out which commands are aliased, query program text segment size and data segment size, trusted X11 forwarding, getting information on the hard drive including the current temperature, using Gnuplot, POVRAY and making animated GIFs, monitoring selective traffic with tcpdump and netstat, multiple examples using the find command, getting the most from Bash, plus a lot more. You can also down this article as a text document here for easy grepping.
Linux Quota Tutorial: This tutorial walks you through implementing disk quotas for both users and groups on Linux, using a virtual filesystem, which is a filesystem created from a disk file. Since quotas work on a per-filesystem basis, this is a way to implement quotas on a sub-section, or even multiple subsections of your drive, without reformatting. This tutorial also covers quotactl, or quota's C interface, by way of an example program that can store disk usage in a SQLite database for monitoring data usage over time.
Breaking Firewalls with OpenSSH and PuTTY: If the system administrator deliberately filters out all traffic except port 22 (ssh), to a single server, it is very likely that you can still gain access other computers behind the firewall. This article shows how remote Linux and Windows users can gain access to firewalled samba, mail, and http servers. In essence, it shows how openSSH and Putty can be used as a VPN solution for your home or workplace.
Create a Live Linux CD - BusyBox and OpenSSH Included : These steps will show you how to create a functioning Linux system, with the latest 2.6 kernel compiled from source, and how to integrate the BusyBox utilities including the installation of DHCP. Plus, how to compile in the OpenSSH package on this CD based system. On system boot-up a filesystem will be created and the contents from the CD will be uncompressed and completely loaded into RAM -- the CD could be removed at this point for boot-up on a second computer. The remaining functioning system will have full ssh capabilities. You can take over any PC assuming, of course, you have configured the kernel with the appropriate drivers and the PC can boot from a CD. This tutorial steps you through the whole processes.
SQLite Tutorial : This article explores the power and simplicity of sqlite3, first by starting with common commands and triggers, then the attach statement with the union operation is introduced in a way that allows multiple tables, in separate databases, to be combined as one virtual table, without the overhead of copying or moving data. Next, the simple sign function and the amazingly powerful trick of using this function in SQL select statements to solve complex queries with a single pass through the data is demonstrated, after making a brief mathematical case for how the sign function defines the absolute value and IF conditions.
The Lemon Parser Tutorial: This article explains how to build grammars and programs using the lemon parser, which is faster than yacc. And, unlike yacc, it is thread safe.
How to Compile the 2.6 kernel for Red Hat 9 and 8.0 and get Fedora Updates: This is a step by step tutorial on how to compile the 2.6 kernel from source.
Virtual Filesystem: Building A Linux Filesystem From An Ordinary File. You can take a disk file, format it as ext2, ext3, or reiser filesystem and then mount it, just like a physical drive. Yes, it then possible to read and write files to this newly mounted device. You can also copy the complete filesystem, sinc\ e it is just a file, to another computer. If security is an issue, read on. This article will show you how to encrypt the filesystem, and mount it with ACL (Access Control Lists), which give you rights beyond the traditional read (r) write (w) and execute (x) for the 3 user groups file, owner and other.
Working With Time: What? There are 61 seconds in a minute? We can go back in time? We still tell time by the sun?
Errata
Special thanks to the following people who pointed out needed corrections.
[Wed May 4 15:34:47 EDT 2005] Martin DiViaio, who pointed out the .fetchmailrc file was setup for comcast and not gmail.
[Wed Jun 29 09:09:52 EDT 2005] Max Waterman, who pointed out spelling mistakes. in 4.2 and 4.3.
[Thu Nov 3 09:30:54 EST 2005] Aleksic Predrag, confirmed trouble with OpenSSL 0.9.8, and pointed out 2nd reference in article. Readers should use 0.9.7i.
[Wed Dec 14 18:07:42 EST 2005] Henk Bokhoven, noted change from Thawte to Equifax.
[Thu Dec 15 04:59:44 EST 2005] Henk Bokhoven, noted Patrick Koetter updated his version of saslfinger to 1.0.
[Sun Mar 5 02:13:18 EST 2006] Rajeev Tandon, noted Makefile changes for Cyrus SASL version 2.1.1.
[Sun Mar 5 12:46:21 EST 2006] Rajeev Tandon, noted that the openssl command in 5.1 should be changed from smtp.gmail.com to pop.gmail.com.
[Sun Oct 12 08:54:21 EDT 2008] Seb Olney, noted needed port change in transport file.
Mike Chirico, a father of triplets (all girls) lives outside of
Philadelphia, PA, USA. He has worked with Linux since 1996, has a Masters
in Computer Science and Mathematics from Villanova University, and has
worked in computer-related jobs from Wall Street to the University of
Pennsylvania. His hero is Paul Erdos, a brilliant number theorist who was
known for his open collaboration with others.
Mike's notes page is souptonuts. For
open source consulting needs, please send an email to
mchirico@comcast.net. All consulting work must include a donation to
SourceForge.net.