Originally posted by: CHPrjohnso

We use the mail command to send notifications from the AIX servers to various e-mail accounts.
Can anyone tell me - does it use smtp as the default mail server? I don't seen anything overwritten in /etc/sendmail.cf. I don't even know if sending mail out uses sendmail.cf.

Problem is that the mail group shutdown a couple old mail servers and we lost the ability to send mail out from the AIX servers. We don't have any entries in /etc/hosts for these mail servers. We use DNS which seems to resolve smtp.xxxxx.org correctly using nslookup. Where could it be referencing the old mail server?

Thanks!
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Originally posted by: Kosala

Hi, mail command is used to send mails to the internal mailer, which you can relayed to another SMTP server for external delivery.

You might be having a configuration in your sendmail.cf file with a configuration similar to DSxxxxxx. The "xxxxx" part is your mail relay, your troubleshooting should start from the mail relay.

For a start, try "telnet your.mail.relay 25" and see whether you get a connection successfully. If it doesn't then you have your problem... if it does connect then you need to speak SMTP to figure things out.

HTH,
Kosala
#AIX-Forum

Originally posted by: CHPrjohnso

Thank you for your response. Even when our e-mails were not arriving at their destinations, I could ping the SMTP servers:

1. telnet smtp.xxxxx.org 25

Trying...
Connected to smtp.xxxxx.org.
Escape character is '^]'.
220 SPETEXCHUBW303.AD.XXXXX.ORG Microsoft ESMTP MAIL Service ready at Tue, 17 J an 2012 10:30:10 -0500

In /etc/sendmail.cf, DS is NULL:

1. "Smart" relay host (may be null)

DS

How does mail know to use smtp.xxxx.org? Is that a default internal mail server?
I made sure that none of our servers include any smtp server in /etc/hosts months ago.
I made sure that /etc/resolv.conf points to the correct DNS servers on all our servers.
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Originally posted by: The_Doctor

just a WAG...... sounds to me like someone might have had:

DShost_name_of_a_mail_relay_server

coded in sendmail.cf at one time, then changed it to:

DS

but never refreshed sendmail or haven't re-booted since then.

Thus mail continud to work until that mail relay server got taken down.

Anyway, just a WAG..... it may fit your situation (or not).
#AIX-Forum

Originally posted by: Kosala

Can you check whether there is a file /etc/mail/sendmail.cf. IIRC this is the sendmail.cf file.

Kosala
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Originally posted by: CHPrjohnso

1. We have rebooted several of these servers which have the problem. So everything should be refreshed.

2. There is a file /etc/mail/sendmail.cf However, it also has DS as null
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Originally posted by: The_Doctor

1. We have rebooted several of these servers which have the problem. So everything should be refreshed.

• sure it's refreshed now, but that doesn't explain why it worked for so long, & now it doesn't work. Which is why I suggested, maybe someone messed with sendmail.cf, removed the DSxxxxxxxx & replaced it with DS, & failed to do the refresh. mail continues to work fine until the next refresh.... then mail falls on the floor & you're left struggling to figure out why. But you know your system better than I, so I'll move along.

2. There is a file /etc/mail/sendmail.cf However, it also has DS as null

FWIW.....

• there should only be one sendmail.cf file and it should be in /etc/mail/
• I would expect /etc/sendmail.cf to be a link to /etc/mail/sendmail.cf

#AIX-Forum

Originally posted by: CHPrjohnso

Thanks...

I think I can rule out someone here changing that value. Some of these servers are fairly new.

Yes, the sendmail.cf is as you say:
lrwxrwxrwx 1 root system 21 Apr 16 2010 /etc/sendmail.cf -> /etc/mail/sendmail.cf

I am suspecting some kind of DNS issue, not a problem on our AIX servers.

So, if we don't specify a "DS" option, the default internal mail server is "smtp"?
#AIX-Forum

Originally posted by: The_Doctor

Is there a default ? I dunno.... I always code a DS value, pointing to my mail relay server.

Have a look thru the file:

/var/adm/maillog 

I suspect this will give you a clue as to what is going on.
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Originally posted by: mmveiga

Run nslookup , then type :

set type=mx
Yourdomainname

What are the mail servers reported by your DNS server to your domain ? The new or the old ?

Regards,
Marcelo.
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Originally posted by: CHPrjohnso

a-ha! It is pointing to the old mail server.

I'll see if this can be corrected in DNS! Or if not, we will have to update sendconf.cf on all our servers. But I hope this is just a DNS correction.

Thank you!
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