DSN: Service unavailable

[BFA6]

Hi all,

I get the above message in /var/adm/syslog/mail.log when sending to an address outside our domain.
If our domain is fred.com, then I can send a message to joe@fred.com without any problems. If I send a message to joe@joe.com then I get the DSN message and the mail isn't delivered. Looking at the log files this only started happening over the last 3 months & I haven't altered anything on the server in that time.

Any help would be appreciated.

Thanks,

Hilary

[Bharat Katkar]

Hi Hilary,
I doubt the /etc/nsswitch.conf file. PLease have a look at it.

Regards,

[BFA6]

This is /etc/nsswitch.conf

hosts: files dns
services: files
protocols: files
networks: files
rpc: files
netgroup: files

I also have another server which has the same problem, but this second server does not use dns at all.

Regards,

Hilary

[Hoefnix]

Hi,

Is the domain that you like to send to resolved by your DNS server. (try a nslookup outsidedomain.com from the server that you want to use for sending the mail)

If DNS is not resolving it, I alway test with putting a fake IP in my /etc/hosts file like:
1.1.1.1 outsidedomain.com

Sendmail on HP_UX likes to resolve domains before sending a message. (with the fake IP it will send the mail to your relay host)

HTH,
Peter

[BFA6]

Hi Peter,

I can't resolve the outside domain, so I put in a fake IP address, but I still get the DSN: Service unavailable message in the mail.log, and so far nothing delivered.

Thanks,

Hilary

[Bharat Katkar]

Nsswitch file seems to be Okay.
What remains is resolv.conf, check that one also and try doing nslookup to your DNS server.

/etc/resolv.conf
search
nameserver

Then try doing nslookup
# nslookup

Hope that helps

[Hoefnix]

Hilary,

Have a look at next thread:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=523534

There is allot of debug information in it.

Next thread can also intererst you:
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=276093


HTH,
Peter

[Rgomes]

Hi,

What does 'sendmail -v joe@joe.com' say?

regards,
Richard

[BFA6]

This is the output of sendmail -v

sendmail -v joe@joe.com
test mail mesage
.
joe@joe.com... Connecting to mailhost via relay...
220 mail.mydomain.com ESMTP Service (Lotus Domino Release 5.0.12) r
eady at Wed, 19 May 2004 09:44:08 +0100
>>> EHLO mybox.mydomain.com
250-mail.mydomain.com Hello mybox.mydomain.com ([1.1.1.1]),
pleased to meet you
250-HELP
250-SIZE -1819869184
250 PIPELINING
>>> MAIL From: SIZE=17
250 hilary@mydomain.com... Sender OK
>>> RCPT To:
554 Relay rejected for policy reasons.
joe@joe.com... Service unavailable
>>> RSET
250 Reset state
/home/hilary/dead.letter... Saved message in /home/hilary/dead.letter
Closing connection to mailhost
>>> QUIT
221 mail.mydomain.com SMTP Service closing transmission channel

Not sure what the policy reasons are, or where they are - I guess the policy is on the mailhost

Regards,

Hilary

[Rgomes]

Hi Hilary,

I suspect, you don't have reverse DNS entry for your mail server.

regards,
Richard

[BFA6]

Richard,

I do have forward and reverse lookup for the mailhost.

Regards,

Hilary

[Rgomes]

And also check the below link:

http://www.experts-exchange.com/Applications/Email/Lotus_Notes_Domino/Q_20883684.html

regards,
Richard

[BFA6]

Thanks for the help - I need to speak to our Lotus Notes administrator to see if the problem lies with the Lotus server.

Thanks,

Hilary

[Joseph Loo]

just curious, have u try

# telnet 25
what is the output?

regards.

[BFA6]

telnet mailhost 25
Trying...
Connected to mailhost.
Escape character is '^]'.

It's not a problem connecting to the mailhost as mails for the internal domain go through without any problems.

Regards,

Hilary

[Joseph Loo]

hi,

then, i can only offer u this link to your Lotus Note administrator.

http://www.dominozone.net/domzone/dzCMS.nsf/web/DZFightingSpamInDomino?OpenDocument&display=email

regards.

[Howard Yuen]

Dear Hilary,

Not sure if you have resolved this ticket yet. But I noticed, your sendmail test routed email to "mail.mydomain.com" and you are referencing "mailhost" during your telnet to port 25. Are they the same box?
Do you have a DS (smart relay host) setting in sendmail.cf? Also check the MX order of the mail server you are using in the DNS and make sure that mail server is the primary MX for itself. Instead of some other mail server (like the primary mx for the domain).

eg.

mx2 IN A 1.1.1.2
IN MX 10 mx2.mydomain.com.
IN MX 15 mx1.mydomain.com.

Thx,
Howard

[Rgomes]

Howard is right. DS macro need to be set for smart relay host.

regards,
richard

[BFA6]

Hi,

The DS macro is set. The Lotus Notes administrator has looked at this, and it would appear that the Lotus Notes box is not relaying messages, and for some reason the administrator cannot make the change stick. It is now being left until Lotus Notes is upgraded.

Thanks for all the replies.

Hilary