I'm running sendmail on several RH6 servers but on one server I didn't manage to make it work. The configuration is the same on all servers. Nevertheless sendmail does not send emails to the smtp server fro this server.
In the maillog I see such entries:
sm-msp-queue[18476]: t2O0F1IO006630: to=root, ctladdr=root (0/0), delay=2+08:34:17, xdelay=00:00:00, mailer=relay, pri=5700416, relay=[127.0.0.1], dsn=4.0.0, stat=Deferred: Connection timed out with [127.0.0.1]
A lot of error mails are queued in /var/spool/clientmqueue/.
For me it looks like sendmail does not recognize the smtp settings.

Any ideas what the problem could be?
Thanks
Guenter

Check your /etc/hosts file. Make sure that there are entries for ipv4 localhost and ipv4 local server hostname at least.
Check your netstat report and see that it is listening on port 25 at address 127.0.0.1
Let us know what you discover.

The /etc/hosts is
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6

It is listening on port 25:
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN

That looks fine for a client machine. The SMTP server, are you using it for a SMARTHOST or RELAY, or is it the target mail server for the TO: accounts?

It's the target mail server for outgoing mails

So, you are send mail form box #1 to email accounts that are on box #2 and NOT to (for example) gmail or yahoo accounts.

I assume, then, that Box #2 is the email server for your domain and is the target of your MX record. Check that /etc/resolv.conf is the same on box #1 as on the other boxes. Perhaps it is not quite getting DNS lookups right, and has not figured out where the mail for your domain should go.

We need not look at the listener on box #2, because it IS receiving mail from your other hosts. Unless there is something there BLOCKING box #1, the issue is more likely to be directly on box #1.

You might want to copy the sendmail.cf from some other box where email works, and this box #1 where it does not, to a safe location and run diff against them. If they differ, it may pay to know why.

Check the access database in /etc/mail on box #2, and make sure that mail is allowed from box #1. It would be silly, but sufficient to cause the issue, if all other hosts were allowed to send it mail but not this one.

/etc/resolv.conf are the same on every box. The sendmail.cf is also exactly the same.
I will get in touch with the admins of box #2 for checking about any blocking.
Thanks so far.
Btw, I will be off for ~1 week due to Easter holidays.

The admins of box #2 confirmed there is no blocking.

you do know that"RH6" is very old and has been unsupported for a very long time

RH6 was released LAST CENTURY !! "26 April 1999"

it predates windows XP

John,
I think he means RHEL6, which is in current support.


Ggrein,
Can you send an email from one account on this box to another successfully? Perhaps we have been looking too far out and the problem is closer.

well there is a rather BIG difference in
RH6 and RHEL 6.x

Dear all,
I managed to fix this problem myself. It was a stupid newbie error. Iptables blocked all mail traffic.
Thanks a lot for all your time and help.
Guenter