Posted By Pierre-Yves Dubreucq on Avr 12, 2010 | 19 comments

Voici un petit tuto permettant d’utiliser le smtp de gmail en smarthost (relay) avec le serveur de messagerie Postfix sur la distribution Ubuntu Server, ici une 9.10.

Bien sur, vous devez avoir au préalable votre serveur Postfix d’installé.

Il vous faut générer un certificat SSL pour votre serveur

Aller dans votre $HOME

root@votrehostname:~#cd ~

Puis générer le nouveau certificat :

Création du fichier « Certificate Authority »

$ /usr/lib/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:
Verifying - Enter PEM pass phrase:
-----
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) [AU]:FR
State or Province Name (full name) [Some-State]:Nord
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:Votre Organisation
Organizational Unit Name (eg, section) []:
Common Name (eg, YOUR name) []:votrehostname
Email Address []:[email protected]

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
Using configuration from /usr/lib/ssl/openssl.cnf
Enter pass phrase for ./demoCA/private/cakey.pem:
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number:
c4:22:ea:51:7c:ba:68:9b
Validity
Not Before: Apr 12 09:52:02 2010 GMT
Not After : Apr 11 09:52:02 2013 GMT
Subject:
countryName               = FR
stateOrProvinceName       = Nord
organizationName          = Votre Organisation
commonName                = votrehostname
emailAddress              = [email protected]
X509v3 extensions:
X509v3 Subject Key Identifier:
72:94:AE:2C:47:9E:A2:6E:28:6B:1A:68:51:E5:5A:3D:93:86:8C:95
X509v3 Authority Key Identifier:
keyid:72:94:AE:2C:47:9E:A2:6E:28:6B:1A:68:51:E5:5A:3D:93:86:8C:95
DirName:/C=FR/ST=Nord/O=Votre Organisation/CN=votrehostname/[email protected]
serial:C4:22:EA:51:7C:BA:68:9B

X509v3 Basic Constraints:
CA:TRUE
Certificate is to be certified until Apr 11 09:52:02 2013 GMT (1095 days)

Write out database with 1 new entries
Data Base Updated

Générer le certificat Serveur :

root@votrehostname:~# openssl req -new -nodes -subj '/CN=votrehostname/O=Votre Organisation/C=FR/ST=Nord/[email protected]' -keyout FOO-key.pem -out FOO-req.pem -days 3650
Generating a 1024 bit RSA private key
................................++++++
.++++++
writing new private key to 'FOO-key.pem'
-----

Vous constaterez bien sur que j’utilise les valeurs données plus haut.

Signer le certificat :

root@votrehostname:~# openssl ca -out FOO-cert.pem -infiles FOO-req.pem
Using configuration from /usr/lib/ssl/openssl.cnf
Enter pass phrase for ./demoCA/private/cakey.pem:
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number:
c4:22:ea:51:7c:ba:68:9c
Validity
Not Before: Apr 12 09:57:23 2010 GMT
Not After : Apr 12 09:57:23 2011 GMT
Subject:
countryName               = FR
stateOrProvinceName       = Nord
organizationName          = Votre Organisation
commonName                = votrehostname
emailAddress              = [email protected]
X509v3 extensions:
X509v3 Basic Constraints:
CA:FALSE
Netscape Comment:
OpenSSL Generated Certificate
X509v3 Subject Key Identifier:
D8:65:D7:DA:68:6C:34:00:14:63:98:B0:BD:C9:9D:67:A0:04:74:2E
X509v3 Authority Key Identifier:
keyid:72:94:AE:2C:47:9E:A2:6E:28:6B:1A:68:51:E5:5A:3D:93:86:8C:95

Certificate is to be certified until Apr 12 09:57:23 2011 GMT (365 days)
Sign the certificate? [y/n]:y

1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated

Copier les certificats dans votre dossier postfix :

root@votrehostname:~# mkdir /etc/postfix/certif
root@votrehostname:~# cp demoCA/cacert.pem FOO-key.pem FOO-cert.pem /etc/postfix/certif
root@votrehostname:~# chmod 644 /etc/postfix/certif/FOO-cert.pem /etc/postfix/certif/cacert.pem
root@votrehostname:~# chmod 400 /etc/postfix/certif/FOO-key.pem

Gmail utilise un certificat Thawte Premium Server CA.

Il vous faut l’ajouter dans le fichier :

root@votrehostname:~# cat /etc/ssl/certs/Thawte_Premium_Server_CA.pem >> /etc/postfix/certif/cacert.pem

Si vous ne faites pas ça, vous aurez le message suivant :

Server certificate not trusted

Attention il semblerait que Gmail a changé de certificat, je m’en suis rendu compte le 27 Mai 2010.

Il n’utilise plus un certicat Thawte mais Equifax

J’ai rencontré ce message d’erreur :

May 23 06:53:21 hostname postfix/smtp[20658]: certificate verification failed for smtp.gmail.com[209.85.229.109]:587: untrusted issuer /C=US/O=Equifax/OU=Equifax Secure Certificate Authority

Pour palier à ce problème, il suffit d’ajouter le bon certificat :

root@votrehostname:~# cat /etc/ssl/certs/Equifax_Secure_CA.pem >> /etc/postfix/cacert.pem

Configuration du serveur Postfix :

Pour cela, il faut modifier le fichier /etc/postfix/main.cf

## TLS Settings
#
smtp_tls_CAfile = /etc/postfix/certif/cacert.pem
smtp_tls_cert_file = /etc/postfix/certif/FOO-cert.pem
smtp_tls_key_file = /etc/postfix/certif/FOO-key.pem
smtp_tls_session_cache_database = btree:/var/run/smtp_tls_session_cache
smtp_use_tls = yes
smtpd_tls_CAfile = /etc/postfix/certif/cacert.pem
smtpd_tls_cert_file = /etc/postfix/certif/FOO-cert.pem
smtpd_tls_key_file = /etc/postfix/certif/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
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

relayhost = [smtp.gmail.com]:587
transport_maps = hash:/etc/postfix/transport

Ajouter dans le fichier /etc/postfix/transport

gmail.com               smtp:[smtp.gmail.com]:587

Ajouter dans le fichier /etc/postfix/sasl_passwd

 [smtp.gmail.com]:587 [email protected]:password

Puis :

postmap sasl_passwd
postmap transport
/etc/init.d/postfix restart

Voilà, votre serveur est configuré

Nettoyer la création de certificat :

root@votrehostname:~# cd ~
rm FOO-req.pem FOO-cert.pem FOO-key.pem && rm -r demoCA/

Tester l’envoie de mail :

J’ai pour habitude de tester l’envoie de mail via telnet :

root@votrehostname:/etc/postfix# telnet localhost 25
Trying ::1...
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 hostname ESMTP Postfix (Ubuntu)
EHLO [email protected]
250-hostname
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
MAIL FROM:[email protected]
250 2.1.0 Ok
RCPT TO:[email protected]
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
Subject:test

test envoi de mail

.
250 2.0.0 Ok: queued as 9D381812
quit
221 2.0.0 Bye
Connection closed by foreign host.

Ce qui est en gras est a renseigner par vos soins bien sur 😉

Pour vérifier, faite un petit

mailq

ou

postqueue -p

Et vérifier dans le fichier /var/log/mail.log que vous n’avez pas d’erreur.

A noter : La flèche utilisée pour illustrer cet article est sous licence libre, mais je ne sais pas laquelle et a été trouvée sur icones.pro