sendmail relay access denied

techrolla · 06-08-2005, 12:50 AM

I have searched through the forums for answers to this, and the closest I could find was a dead-end topic here: http://www.linuxquestions.org/questi...+access+denied

I have postfix setup, and I can send and recieve email fine from local users to local users and from outside to local, but I can't send email to outside sources such as yahoo.com and hotmail. I tested it and saw the SMTP commands, and I am getting 554: Relay access denied back from these servers. Could the problem be in my resolv.conf?

Here is resolv.conf:

Code:

domain localhost
nameserver 192.168.2.1
search WorkGroup

and my postconf -n:

Code:

alias_database = hash:/etc/mail/aliases
alias_maps = hash:/etc/mail/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/lib/postfix
debug_peer_level = 2
html_directory = no
inet_interfaces = all
mail_owner = postfix
mailq_path = /usr/bin/mailq
manpage_directory = /usr/share/man
mydestination = $mydomain $myhostname localhost.$mydomain
mydomain = muffinpeddler.com
myhostname = mail.muffinpeddler.com
newaliases_path = /usr/bin/newaliases
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.1.5-r1/readme
sample_directory = /etc/postfix
sendmail_path = /usr/sbin/sendmail
setgid_group = postdrop
smtpd_banner = $myhostname ESMTP $mail_name :: Mail!
unknown_local_recipient_reject_code = 450

I have a domain that I am using, but it resolves to my computer dynamically with freedns.afraid.org. Any suggestions? Thanks!

techrolla · 06-10-2005, 05:27 PM

Any one have any suggestions? I am going crazy! Anyways, what I have is an MX record for 25:mail.mysite.com setup on freedns.afraid.org. I removed the default one for 10:mail.mysite.com. Could it be that my ISP is some how playing a part in this? I can email from outside in just fine, and sometimes I can email from my computer to my account on sbcglobal.net, but that is just sometimes and it never works when I test it in something like zoneedit's smtp check and I can't email anyone else...Also, something odd about the messages that sometimes go through to my account are that they are all flagged as bulk, which might mean something is misconfigured on my side that is raising a flag for the yahoo sbcglobal spam guard?

Thanks.

scowles · 06-10-2005, 08:04 PM

I would start by seeing if your ISP is blocking outbound smtp connections to any mail server other than your ISP's mail server. If this is the case, then you would need to configure postfix to always use your ISP's mail server for outbound e-mail. See the "relayhost" parameter in main.cf

To test, simply telnet to one of yahoo's many MX records on port 25. Example:
[root@excelsior spamassassin]# dig +short yahoo.com mx
1 mx3.mail.yahoo.com.
5 mx4.mail.yahoo.com.
1 mx1.mail.yahoo.com.
1 mx2.mail.yahoo.com.

root@excelsior spamassassin] # telnet mx3.mail.yahoo.com 25
...some output from yahoo
quit
root@excelsior spamassassin]#

If you do not get a response or a timeout, then your ISP is blocking outbound e-mails.

If you do get a response, then your e-mail could be rejected for many other reasons.

1) An invalid HELO response by your postfix server.
2) Your postfix server is connecting from a dynamically assigned IP address.
3) DNS reverse lookup for your IP address by the remote does not match the configured HELO announcement by your postfix server.

FWIW: I have a rule on my postfix server which rejects any MTA connecting from a dynamically assigned IP address. This one rule has literally stoped all virus infected e-mails from being processed and deleted by my MTA. Now if I could only find that magical rule that would stop all SPAM, I would be a happy camper. :-)

techrolla · 06-10-2005, 09:27 PM

Hey, thanks for your reply!

I could not connect to these mail servers...I am going to assume that I can only send outbound mail through the sbcglobal smtp server. However, this server requires authentication. Can I authenticate (if yes, then where should I look for information), and can I still acieve separate user emails through one main account? Thanks a lot.

Keithj · 06-11-2005, 06:28 AM

My understanding is that spam-prevention rules mean that ISPs will not allow you to connect remotely to their SMTP servers. Therefore, the only way you can send mail is through your own ISP's SMTP server.

You can connect to Online services such as Hotmail, Mail.com via the web, but that's a different process.

techrolla · 06-11-2005, 01:59 PM

I contacted sbcglobal and they restrict this by default, but I submitted a request to have it removed. Thanks!