Sendmail vs DNS

[Jorge Prado T]

Hello,
I have the following problem:
When the resolution of names is enabled by DNS sendmail it doesn't distribute the mail (relay).
Alone Sendmail works with the resolution through the host table.
As sendmail it is configured to work with DNS?

S.O. hpux 11i

Thank in advance

Jorge Prado T.

[Patrick Wallek]

Sendmail should work fine with DNS.

You may just need to verify that your /etc/resolv.conf and /etc/nsswitch.conf files are set up properly.

[Sung Oh]

Hi Jorge,

you can run "nslookup" from your server to contact DNS server.

#nslookup www.hp.com

from above result you can check to see if your email server is talking to DNS server or not.

I hope this helps,

Sung

[Bill Hassell · Accepted solution]

The most common cause of sendmail failures (for external destinations) is DNS, namely, MX records. If your DNS server is Windows-based, the admin probably left out MX (mail delivery) records and probably reverse lookup records. If your sendmail has to go through a company mail server like Exchange, your internal DNS server must either provide MX records for all external addresses or you configure sendmail to forward all non-local mail to your Exchange machine (a lot easier). Also make sure that the file /etc/mail/sendmail.cf has valid entries for the local machine's name (simple and canonical) at the bottom of the file. Delete duplicate and incorrect entries in the .cf file.

[Steven E. Protter]

Shalom Jorge,

/var/adm/syslog/mail.log

A log of the errors.

If you have set up sendmail with DS based relay , the most common cause of delivery failure is the server targeted for DS based relay (sendmail.cf) is the relay server is not configured to permit your server to relay.

Common diagnostic technique:

sendmail -v -d8.99 -d38.99 someone@yahoo.com

type some text

.



You will get good diagnostics.

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