Hi All,

i have configured sendmail client in my server after configuration done we are not able to send mails, anyone please help me on this.


Jun 15 13:16:39 test1 sendmail[1867]: t5F7GclF001867: from=<applprod@test1.demo.com>, size=508, class=0, nrcpts=1, msgid=<201506150716.t5F7Gct0001866@test1.demo.com>, proto=ESMTP, daemon=MTA, relay=localhost [127.0.0.1]
Jun 15 13:16:39 test1 sendmail[1866]: t5F7Gct0001866: to=ramesh@demo.com, ctladdr=applprod (54322/54322), delay=00:00:01, xdelay=00:00:01, mailer=relay, pri=30228, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (t5F7GclF001867 Message accepted for delivery)
Jun 15 13:16:39 test1 sendmail[1869]: t5F7GclF001867: to=<ramesh@demo.com>, ctladdr=<applprod@test1.demo.com> (54322/54322), delay=00:00:01, xdelay=00:00:00, mailer=esmtp, pri=120508, relay=demo.com, dsn=5.1.2, stat=Host unknown (Name server: demo.com: no data known)
Jun 15 13:16:39 test1 sendmail[1869]: t5F7GclF001867: t5F7GdlF001869: DSN: Host unknown (Name server: demo.com: no data known)
Jun 15 13:16:39 test1 sendmail[1869]: t5F7GdlF001869: to=<applprod@test1.demo.com>, delay=00:00:00, xdelay=00:00:00, mailer=local, pri=31743, dsn=2.0.0, stat=Sent

While I don't know sendmail, the messages seem to indicate something is wrong with name resolution. Perhaps the MX record for demo.com is not set correctly, or you need to tell sendmail what to do with messages that go to demo.com.

1 members found this post helpful.

How to set the MX record and how to resolve the name resolution, can you please help me on this

Your server is named test1.demo.com. The "demo.com" part is your domain. You are now sending email to ramesh@demo.com. The problem now is: How does the mailing system know to which server the message should be sent?

This problem is solved by the Domain Name System. DNS maps host names to IP addresses, but it can also configure the mail servers for a domain. The MX record in the DNS config file performs that mapping.
You can see the MX records of a domain with commands like host or nslookup, e.g. nslookup -type=MX google.com or host -t MX google.com.

So, for your domain demo.com you need a DNS server that contains an MX record. If you have such a server, put its IP address in the /etc/resolv.conf file. If not, you need to configure one. I can't describe DNS setup in a forum post, but the internet is full of recipes for that. It's not really for beginners, so that you learning curve might be steep, but you would learn a lot in the process.

However, if you are not interested in setting up MX records, just test your mailing system by sending a message to ramesh@test1.demo.com. In other words, use the specific system name where ramesh has an account rather than the domain.

hi,

Thanks for clarification.
We are having 2 dns servers and 1 sendmail server(10.10.1.18)


host -t MX demo.com
demo.com has no MX record


cat /etc/resolv.conf
# Generated by NetworkManager
search demo.com
nameserver 10.10.1.23
nameserver 10.10.1.24

So you have to add an MX record to the DNS server(s)

Looks like you normally use 10.10.1.23; if it doesn't respond, the other one.

You will have to add an MX record to the zone file of demo.com. See https://en.wikipedia.org/wiki/Zone_file for what that looks like; where that zone file is depends on your configuration and the Linux distro you are using.

hi,

Is there any other way to by-pass the DNS server?