Solaris - Sendmail - Adding .com.gr in external senders e-mails

UNIX Solaris
1

Hello Everybody !

I'm Harry from Athens Greece and i have a problem with my Sendmail 8.13.3 installed on Solaris SunOS ultra 5.10.

The problem is that when someone sends to us an e-mail and his e-mail address is like : xxxx@xxxx.com, our e-mail server adds up in the senders address a .com.gr in the end.
So the senders address is altered from xxxx@test.com to xxxx@test.com.com.gr

So when a user tries to reply (of course the user never notices the adding of .com.gr in the end) the reply e-mail never reaches any recipient.

If the person who sends us an e-mail has an address like the following the problem never occurs :
xxxxx@x.com.gr
xxxx@x.gr
xxxx@x.x.gr
xxxx@x.x.com

Does anyone had any idea why this could be happening and maybe how i could fix this ?

Thank you very much in advance.
Harry.

2

check the hostname, domain name, dns, and in sendmail config check if masquerading an another host.

3

Thank you jgt !

One thing i haven't said earlier is that when someone is sending us an e-mail, this is delivered in a Fortimail Antivirus-Antispam server and then Fortimail, is forwarding the e-mail to the Solaris sendmail Server in order for the users to get their e-mails.

I have check also the config files of the Fortimail but, nothing there.

I have checked the DNS, hostname and domains (there are 12) already.
They seem to be ok !

I have compared the masquerade the options in the sendmail.cf and submit.cf file with similar sendmail files that i found in the web, they also seem to be ok.

I am missing something...