Sendmail not relaying

[gemo]

Hi:
I have a peculiar problem.
Server A hostname is abc, domainname is foobar.com with ip
123.23.23.123
Server A dns entry is cab.foobar1.com with the same ip as mentioned above
Server B hostname is xyz, domainame is foobar1.com

Sendmail config on Server A has Server B has the relay host.
When I send mail to my exchange account, from Server A, I get the following message on the relay host ( Server B )

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Nov 30 19:18:19 xyz sendmail[12875]: jAUJIJp9012875: from=<root@abc.foobar.com>, size=484, class=0, nrcpts=1, msgid=<200511301918.jAUJIJ9p007481@abc.foobar.com>, proto=ESMTP, daemon=MTA, relay=abc [206.24.18.228]

Nov 30 19:18:21 xyz sendmail[12877]: jAUJIJp9012875: to=<myself@foobar.com>, delay=00:00:02, xdelay=00:00:02, mailer=esmtp, pri=30484, relay=foobar.relay1a.com. [xxx.xxx.xx.xx], dsn=5.1.8, stat=User unknown

Nov 30 19:18:21 xyz sendmail[12877]: jAUJIJp9012875: jAUJILp9012877: DSN: User unknown

Nov 30 19:18:21 xyz sendmail[12877]: jAUJILp9012877: to=<root@abc.foobar.com>, delay=00:00:00, xdelay=00:00:00, mailer=esmtp, pri=31508, relay=abc.foobar.com. [123.23.23.123], dsn=4.0.0, stat=Deferred: abc.foobar.com.: No route to host

--------------------

On the other hand, an application sending mail from Server A can successfully send mail via relay host Server B. Below is the log message for that from the relay host ( Server B )

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maillog:Nov 29 20:33:15 xyz sendmail[27091]: jATKXFp9027091: from=<cab@foobar1.com>, size=549, class=0, nrcpts=1, msgid=<200511292033.jATKXFp9027091@xyz.foobar1.com>, proto=SMTP, daemon=MTA, relay=xyz [123.23.23.123]

maillog:Nov 29 20:33:16 xyz sendmail[27093]: jATKXFp9027091: to=<myself@foobar.com>, delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=30162, relay=foobar.relay1a.com. [xxx.xxx.xx.xxx], dsn=2.0.0, stat=Sent (jATLvaxm030453 Message accepted for delivery)
-------------------------

The message sent by the application is using a different domain name (foobar1.com) than the one sent by me manually. Nslookup on the ip of abc (Server A) gives me cab.foobar1.com as mentioned above.

The questions I have are:
1) How is the application able to send mail as a different hostname
2) What configuration changes should i make so that I can send mail manually

Ur help would be greatly appreciated.

Thanks in advance.

regards

gom

 

[mrballcb]

The No Route to Host error means that it tried to connect to port 25 of 123.23.23.123 and
a) nothing was listening
or
b) there a networking problem and it can't connect to that IP