Postfix is a mail server,or MTA (Mail Transfer Agent). It accepts messages and delivers them. fetchmail is a remote mail retrieval system, providing home users like you, who don't have corporate accounts, the ability to pull mail from an ISP, or in this case Gmail, to your local Linux box. All the examples below have been made with the fake domain name "squeezel", which is my four-year-old's word for the concatenation of "squeeze" and "wheezel".
It is very important to set up fetchmail with some type of encryption. Otherwise, your Gmail password will be broadcast over the Internet every time the fetchmail daemon tries to pick up mail, which could be every 90 seconds. In addition, this tutorial will walk you through building and configuring the latest version of Postfix with TLS and SASL support.
Get the latest version of Postfix. As of this writing, the latest version is 2.2.3, which was released on May 3, 2005. You can find out what version you have with the following command:
$ postconf mail_version mail_version = 2.2.3
From the Postfix homepage, download the latest version.
$ ncftpget ftp://mirrors.loonybin.net/pub/postfix/official/postfix-2.2.3.tar.gz $ ncftpget ftp://mirrors.loonybin.net/pub/postfix/official/postfix-2.2.3.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 <email@example.com>" imported gpg: key D5327CB9: public key "wietse venema <firstname.lastname@example.org>" imported gpg: Total number processed: 2 gpg: imported: 2 (RSA: 2)
Verify that the source is valid:
$ gpg --verify postfix-2.2.3.tar.gz.sig postfix-2.2.3.tar.gz
Extract the files:
$ tar -xzf postfix-2.2.3.tar.gz
Since you're connecting to Google's Gmail, you'll need to compile Postfix with TLS (for encryption) and SASL (for authentication).
Special note: Some older versions of Red Hat 8 and 9 may not have an updated version of openssl. Check to see what version you have with the following command:
$ openssl version OpenSSL 0.9.7g 11 Apr 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
/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
$ ./config --prefix=/usr --openssldir=/usr/share/ssl $ make $ make test $ make install
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
Authentication failed: cannot SASL authenticate to server smtp.gmail.com[126.96.36.199]: no mechanism available
You can get the latest cyrus-sasl package from ftp://ftp.andrew.cmu.edu/pub/cyrus-mail/. Make sure you search for the latest package. As of this writing, the following is the latest:
$ ncftpget ftp://ftp.andrew.cmu.edu/pub/cyrus-mail/cyrus-sasl-2.1.20.tar.gz
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.
At this stage, you've upgraded openssl and sasl. If you have authentication failures, upgrade those packages. I had problems with Fedora Core 3 RPM installs, so I had to go back and 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
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.
Clean 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 -I/usr/include/sasl" \ AUXLIBS="-lssl -lcrypto -lsasl2" Optionx 2: TLS, SASL2, and MySQL. $ make makefiles CCARGS="-DUSE_TLS -DUSE_SASL_AUTH -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", something like this: $ make makefiles CCARGS="-DUSE_TLS -DUSE_SASL_AUTH -I/usr/include/sasl -DHAS_MYSQL -I/usr/include/mysql" \ AUXLIBS="-lssl -lcrypto -L/usr/lib/mysql -lmysqlclient -lz -lm -lsasl2" $ make $ make install
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.
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-2.2.2] 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]
Once you are done, as a check to see if ssl has been compiled into postfix, you can ldd the postfix binary as follows, which will show linked libraries.
$ ldd /usr/sbin/postfix libssl.so.4 => /lib/libssl.so.4 (0x007ae000) libcrypto.so.4 => /lib/libcrypto.so.4 (0x006bb000) libmysqlclient.so.14 => /usr/lib/mysql/libmysqlclient.so.14 (0x00b28000) libz.so.1 => /usr/lib/libz.so.1 (0x00bf1000) libm.so.6 => /lib/tls/libm.so.6 (0x00afd000) libsasl2.so.2 => /usr/lib/libsasl2.so.2 (0x005f6000) libpcre.so.0 => /lib/libpcre.so.0 (0x00d46000) libdb-4.2.so => /lib/tls/i686/libdb-4.2.so (0x00201000) libnsl.so.1 => /lib/libnsl.so.1 (0x007e4000) libresolv.so.2 => /lib/libresolv.so.2 (0x00d30000) libc.so.6 => /lib/tls/libc.so.6 (0x009d1000) libgssapi_krb5.so.2 => /usr/lib/libgssapi_krb5.so.2 (0x006a5000) libkrb5.so.3 => /usr/lib/libkrb5.so.3 (0x0061b000) libcom_err.so.2 => /lib/libcom_err.so.2 (0x005f1000) libk5crypto.so.3 => /usr/lib/libk5crypto.so.3 (0x00682000) libdl.so.2 => /lib/libdl.so.2 (0x00b22000) libcrypt.so.1 => /lib/libcrypt.so.1 (0x032cb000) /lib/ld-linux.so.2 (0x009b7000) libpthread.so.0 => /lib/tls/libpthread.so.0 (0x00c13000)
The first line with "libssl.so" shows that I have ssl installed, then,
six lines down after the command, see "libsasl2.so.2". In my version,
did I choose MySQL? The best way to tell is with the
-m option. But, yes, some of you may have a sharp eye and notice
the "libz" and "libm" links, which go with the MySQL installation.
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
/usr/local/lib/mysql as follows:
$ cat /etc/ld.so.conf ... /usr/local/lib/mysql
After adding this line, you must run the
then all those odd MySQL libraries will be found. It's a good technique
if you install a lot of software from source.
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. See the steps above if you decide to upgrade.
$ openssl version OpenSSL 0.9.7g 11 Apr 2005
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 "Certificate 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 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.
This is the server cert request that will be signed by the CA Authority. Note that the "-nodes" option is used so that the certificate will not require a passphrase 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' \ -keyout FOO-key.pem -out FOO-req.pem -days 3650
Note above that "/0=Chirico_Widgets" must match the name given in the the original CA. For example, "/0=Widgets co." will not work. It must be exact.
The following step will sign the certificate.
$ openssl ca -out FOO-cert.pem -infiles FOO-req.pem
The next step copies 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
/etc/postfix/master.cf are the two basic Postfix
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.)
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". here's
# 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:
Finally, to put all changes into effect, 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.
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.
## Add these lines to the bottom on main.cf ## ## ## TLS Settings # 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 into 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] ## 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 email@example.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. The "*.pem" files appear to be listed twice, but notice the difference between "smtp" and "smtpd". One is for client connectivity and the other is for connecting to this server.
In the above
main.cf file, there are references to 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,
Below is a sample sasl_passwd file. This will log into smtp.gmail.com with username mchirico, using the password pa33w0r8.
# Contents of sasl_passwd # [smtp.gmail.com] firstname.lastname@example.org:pa33w0r8
This file must be converted to hash format with the following commands:
$ cd /etc/postfix $ postmap sasl_passwd
postmap command must be run any time
sasl_passwd is changed, because this creates the
sasl_passwd.db file that Postfix reads.
After you've executed the above command, run this simple "hash" key test:
$ postmap -q [smtp.gmail.com] sasl_passwd email@example.com:pa33w0r8
/etc/postfix/generic contains the following
# Contents of /etc/postfix/transport # # This sends mail to Gmail gmail.com smtp:[smtp.gmail.com] # # Except mail going to the tape and closet servers 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 account. Note that the return address is
"firstname.lastname@example.org" because of the following entry in
This file must by owned by root. Whenever changes are made to this file,
Postfix should be reloaded with
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 will. What about mail from
"squeezel.squeezel.com" to itself? There's no address translation
either, which is a feature of "smtp_generic_maps".
That's it for the server certificate. Postfix will still have to be configured to connect to your ISP.
To see if all the changes 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] 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_session_cache_database = btree:/var/run/smtp_tls_session_cache smtp_use_tls = yes smtpd_sasl_application_name = smtpd smtpd_sasl_auth_enable = no smtpd_sasl_local_domain = $myhostname 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 transport_maps = hash:/etc/postfix/transport unknown_local_recipient_reject_code = 550
$ /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
Instead of using the hash type, you can leverage MySQL. Below is a
smtp_generic_maps configuration for converting
addresses. The text below is the
file. Note that it contains the MySQL username, the password for MySQL,
and the database "dbname". The comments show how this table was created
# 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 ('email@example.com','firstname.lastname@example.org'); # insert into smtpg_maps (address,smtp_address) values ('email@example.com','firstname.lastname@example.org'); # insert into smtpg_maps (address,smtp_address) values ('email@example.com','firstname.lastname@example.org'); # # Test this with # $ postmap -q "email@example.com" mysql:/etc/postfix/generic_mysql # hosts = localhost user = mysqlmail password = S0m3paSSw0r9 dbname = mail query = SELECT smtp_address FROM smtpg_maps WHERE address = '%s'
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:
You will want to select 2. If you then do an "ls" on sendmail, you will 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
Now try sending mail. The "correct" sendmail will build a report that you can view with mutt or your email package. Below is an example test.
$ sendmail -bv firstname.lastname@example.org
Any mail sent from "email@example.com" can be blind copied to another server. In this case, the server is "chirico@tape".
In /etc/postfix/main.cf: sender_bcc_maps = hash:/etc/postfix/bcc_table
postmap bcc_table after editing the bcc_table
In /etc/postfix/bcc_table: firstname.lastname@example.org chirico@tape
If you want to get copies of everything coming in and going out, use the
always_bcc option. I normally create a special user for
this, "allmail". That way, I can forward email easily, if needed.
In /etc/postfix/main.cf: always_bcc = allmail
It's not a completely blind copy, since it will show up when users
on the system do a
sendmail -bv test.
Fetchmail pulls messages from Google's Gmail, since for a home user with a fake domain and changing IP address, their email server will not forward the mail.
Again, it is very important to set up fetchmail with some type of encryption. STARTTLS encryption works well, since you have already installed the necessary openssl files. You just need to pick up the necessary keys and put them in the proper format.
$ openssl s_client -connect smtp.gmail.com:995 -showcerts
The command above will return the certificate from Google's Gmail as follows:
CONNECTED(00000003) --- Certificate chain 0 s:/C=US/ST=California/L=Mountain View/O=Google Inc/CN=pop.gmail.com i:/C=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Server CA/emailAddressemail@example.com -----BEGIN CERTIFICATE----- MIIDRDCCAq2gAwIBAgIDILn5MA0GCSqGSIb3DQEBBAUAMIHEMQswCQYDVQQGEwJa QTEVMBMGA1UECBMMV2VzdGVybiBDYXBlMRIwEAYDVQQHEwlDYXBlIFRvd24xHTAb BgNVBAoTFFRoYXd0ZSBDb25zdWx0aW5nIGNjMSgwJgYDVQQLEx9DZXJ0aWZpY2F0 aW9uIFNlcnZpY2VzIERpdmlzaW9uMRkwFwYDVQQDExBUaGF3dGUgU2VydmVyIENB MSYwJAYJKoZIhvcNAQkBFhdzZXJ2ZXItY2VydHNAdGhhd3RlLmNvbTAeFw0wNDEy MTMxOTQ2MjRaFw0wNTEyMTMxOTQ2MjRaMGcxCzAJBgNVBAYTAlVTMRMwEQYDVQQI EwpDYWxpZm9ybmlhMRYwFAYDVQQHEw1Nb3VudGFpbiBWaWV3MRMwEQYDVQQKEwpH b29nbGUgSW5jMRYwFAYDVQQDEw1wb3AuZ21haWwuY29tMIGfMA0GCSqGSIb3DQEB AQUAA4GNADCBiQKBgQDF6HmquCQW7cS7pI1KIrklmLCEOqj6+kC+PoJx9F2TMZqs hYVHM85ZJypj2Uv1q6zOjd/34DAkKmYZK9mVbY6I+PsMl0Azyn910sdQ9k9yN2tc nCQBpKE38IN97tISL3xbqRsdLTsw94B3PS9A735MX7EGXG1tX/6GnUqTiQqJIwID AQABo4GfMIGcMB0GA1UdJQQWMBQGCCsGAQUFBwMBBggrBgEFBQcDAjA5BgNVHR8E MjAwMC6gLKAqhihodHRwOi8vY3JsLnRoYXd0ZS5jb20vVGhhd3RlU2VydmVyQ0Eu Y3JsMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDovL29jc3AudGhh d3RlLmNvbTAMBgNVHRMBAf8EAjAAMA0GCSqGSIb3DQEBBAUAA4GBAD4f2AcBn4WD eF07St93dsdbqGYdlMrCquN6yd6WvYoNRosX0N4nMtKTJN6CNAgs2lvfL1qSChYf NX4LosLm3OzM9KGSMVAiG7lsu9sQULX+GH8h7HLBlOOKWhnOyf3TNL5kZeGj9NL8 L83QaTlPJVKkwLgKVGM8Yk349y32Nr9D -----END CERTIFICATE----- --- Server certificate subject=/C=US/ST=California/L=Mountain View/O=Google Inc/CN=pop.gmail.com issuer=/C=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Server CA/emailAddressfirstname.lastname@example.org --- No client certificate CA names sent --- SSL handshake has read 994 bytes and written 332 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: 99413B0588D17E638E5F2992DEE68393F1B4FF477A0B4318B8B2651E85C63D77 Session-ID-ctx: Master-Key: 97BD90B0EF9F3C77013CF8F42077838C518A30EBAD18BDD9E6B8500E8221BC0B82DD2CC4F9DFC84814960E1EF609EB1C Key-Arg : None Start Time: 1117819950 Timeout : 300 (sec) Verify return code: 21 (unable to verify the first certificate) --- +OK Gpop g2pf1372524wra ready.
Next, you need to copy the certificate part, which is everything between "BEGIN CERTIFICATE" and "END CERTIFICATE", and save this to a file.
-----BEGIN CERTIFICATE----- ... d3RlLmNvbTAMBgNVHRMBAf8EAjAAMA0GCSqGSIb3DQEBBAUAA4GBAD4f2AcBn4WD eF07St93dsdbqGYdlMrCquN6yd6WvYoNRosX0N4nMtKTJN6CNAgs2lvfL1qSChYf NX4LosLm3OzM9KGSMVAiG7lsu9sQULX+GH8h7HLBlOOKWhnOyf3TNL5kZeGj9NL8 L83QaTlPJVKkwLgKVGM8Yk349y32Nr9D -----END CERTIFICATE-----
Notice that the CA for this certificate is thawte.com, which means you
need that certificate as well. This is a very common certificate. You
can copy and paste it from
/usr/share/ssl/cert.pem, or you
can copy it from below.
Thawte Server CA ================ MD5 Fingerprint: C5:70:C4:A2:ED:53:78:0C:C8:10:53:81:64:CB:D0:1D PEM Data: -----BEGIN CERTIFICATE----- MIIDEzCCAnygAwIBAgIBATANBgkqhkiG9w0BAQQFADCBxDELMAkGA1UEBhMCWkEx FTATBgNVBAgTDFdlc3Rlcm4gQ2FwZTESMBAGA1UEBxMJQ2FwZSBUb3duMR0wGwYD VQQKExRUaGF3dGUgQ29uc3VsdGluZyBjYzEoMCYGA1UECxMfQ2VydGlmaWNhdGlv biBTZXJ2aWNlcyBEaXZpc2lvbjEZMBcGA1UEAxMQVGhhd3RlIFNlcnZlciBDQTEm MCQGCSqGSIb3DQEJARYXc2VydmVyLWNlcnRzQHRoYXd0ZS5jb20wHhcNOTYwODAx MDAwMDAwWhcNMjAxMjMxMjM1OTU5WjCBxDELMAkGA1UEBhMCWkExFTATBgNVBAgT DFdlc3Rlcm4gQ2FwZTESMBAGA1UEBxMJQ2FwZSBUb3duMR0wGwYDVQQKExRUaGF3 dGUgQ29uc3VsdGluZyBjYzEoMCYGA1UECxMfQ2VydGlmaWNhdGlvbiBTZXJ2aWNl cyBEaXZpc2lvbjEZMBcGA1UEAxMQVGhhd3RlIFNlcnZlciBDQTEmMCQGCSqGSIb3 DQEJARYXc2VydmVyLWNlcnRzQHRoYXd0ZS5jb20wgZ8wDQYJKoZIhvcNAQEBBQAD gY0AMIGJAoGBANOkUG7I/1Zr5s9dtuoMaHVHoqrC2oQl/Kj0R1HahbUgdJSGHg91 yekIYfUGbTBuFRkC6VLAYttNmZ7iagxEOM3+vuNkCXDF/rFrKbYvScg71CcEJRCX L+eQbcAoQpnXTEPew/UhbVSfXcNY4cDk2VuwuNy0e982OsK1ZiIS1ocNAgMBAAGj EzARMA8GA1UdEwEB/wQFMAMBAf8wDQYJKoZIhvcNAQEEBQADgYEAB/pMaVz7lcxG 7oWDTSEwjsrZqG9JGubaUeNgcGyEYRGhGshIPllDfU+VPaGLtwtimHp1it2ITk6e QNuozDJ0uW8NxuOzRAvZim+aKZuZGCg70eNAKJpaPNW15yAbi8qkq43pUdniTCxZ qdq5snUb9kLy78fyGPmJvKP/iiMucEc= -----END CERTIFICATE-----
Once you have created these files, you will need to run the
c_rehash command to create the necessary symlinks. I've
copied the files to
/home/chirico/certs/.certs. Then, I do
[chirico@squeezel certs]$ c_rehash .certs Doing .certs googlepop.pem => 34ceaf75.0 thawte.pem => ddc328ff.0
It's possible to check the certificates as with the
s_client command as follows:
$ openssl s_client -connect pop.gmail.com:995 -CApath /home/chirico/certs/.certs/ CONNECTED(00000003) depth=1 /C=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Server CA/emailAddressemail@example.com 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=ZA/ST=Western Cape/L=Cape Town/O=Thawte Consulting cc/OU=Certification Services Division/CN=Thawte Server CA/emailAddressfirstname.lastname@example.org --- Server certificate -----BEGIN CERTIFICATE----- ... [SNIP] ... --- +OK Gpop ready.
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 # # The Gmail username is mchirico, but on this computer, it is chirico. # To keep mail on the server, put "keep" at the end. # user 'email@example.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 'firstname.lastname@example.org' 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'
Here are some of the more common fetchmail commands:
$ fetchmail -q # quits the fetchmail daemon $ fetchmail -v # start the fetchmail daemon in verbose mode $ fetchmail -c # checks for email only $ fetchmail -S localhost # delivers mail to your Postfix server
Normally, you want to start fetchmail with the "-v" option and take a
look at the
/var/log/maillog files for any problems.
Your home computer should now be all set to send and receive mail through Google. Happy Gmailing!