Postfix cannot relay emails from other domains

[dalitso]

I have a machine running Ubuntu server 8.04 with all the services I configured running ok. I use webmin to do my configurations and also have a dyndns hostname for the server. I can send and receive emails with postfix on the server.

I have a client machine which has Thunderbird setup to send and receive mail through the server. The problem is that, I can only relay emails from my dyndns hostname only. I cannot send other domain emails like gmail ( if I setup the from email in thunderbird as me@mydyndns.com it sends but not me@gmail.com)

Someone told me this is because by default ubuntu server is not an open relay server. Is there a way I can allow certain domains to send emails through?

Your help will be appreciated.

[falko]

Please enable "Server requires authentication" in your email client.

[dalitso]

Still not workinh. Here's error from my mail system log

Jun 3 16:55:53 dalitso postfix/smtp[19484]: 73C9E2A58F: to=<martin@martinology.co.za>, relay=smtp.isdsl.net[196.26.208.197]:25, delay=181, delays=0.02/0.01/1/180, dsn=5.0.0, status=bounced (host smtp.isdsl.net[196.26.208.197] said: 550-Service unavailable; Sender address [dalitsomaosa@gmail.com] blocked using 550 sdom.bl.isdsl.net ; Access denied (in reply to RCPT TO command))
Jun 3 16:55:53 dalitso postfix/cleanup[19540]: 939EB2A5C5: message-id=<20090603145553.939EB2A5C5@dalitso.mine.nu>
Jun 3 16:55:53 dalitso postfix/qmgr[6742]: 939EB2A5C5: from=<>, size=2624, nrcpt=1 (queue active)
Jun 3 16:55:53 dalitso postfix/bounce[19539]: 73C9E2A58F: sender non-delivery notification: 939EB2A5C5
Jun 3 16:55:53 dalitso postfix/qmgr[6742]: 73C9E2A58F: removed

[falko]

Still not workinh. Here's error from my mail system log

Jun 3 16:55:53 dalitso postfix/smtp[19484]: 73C9E2A58F: to=<martin@martinology.co.za>, relay=smtp.isdsl.net[196.26.208.197]:25, delay=181, delays=0.02/0.01/1/180, dsn=5.0.0, status=bounced (host smtp.isdsl.net[196.26.208.197] said: 550-Service unavailable; Sender address [dalitsomaosa@gmail.com] blocked using 550 sdom.bl.isdsl.net ; Access denied (in reply to RCPT TO command))Your relay server seems to blacklist Gmail addresses...

[dalitso]

Not only gmail addressess, any address other than my dyndns address. Only my dyndns address can be relayed. I have also tried other relay servers but they are still blocking.

How can I solve this?

[dalitso]

Here's my postfix main.cf


smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no


# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# TLS parameters
smtpd_tls_cert_file = /etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file = /etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls = yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = localhost.mine.nu., localhost, dalitso.mine.nu
relayhost = smtp.isdsl.net
mailbox_command = procmail -a $EXTENSION
mailbox_size_limit = 0
recipient_delimiter = +
virtual_alias_maps = hash:/etc/postfix/virtual
mail_spool_directory = /var/spool/mail
home_mailbox = Maildir/
mynetworks = 192.168.1.0/24 127.0.0.0/8 192.168.0.0/24

[falko]

You might have to use authentication for the relayhost - see http://www.howtoforge.com/postfix_relaying_through_another_mailserver

[dalitso]

Thanks alot Falko, using authentication for the relayhost works!

I was just wondering though, is this method supposed to make all email addresses relayable or only the one belonging to the authenticated user name and password? I noticed I can now relay my dyndns email address and the one I setup the authentication for but not the gmail address. My email I authenticate belongs to a different ISP from the one my adsl is subscribed to and I don't use my adsl ISP smtp. Can this be the reason?

[falko]

I was just wondering though, is this method supposed to make all email addresses relayable or only the one belonging to the authenticated user name and password?

All email addresses.