Hello,
I met the problems with Sendmail configuration (I have several domain on one server):
1. when sending email, it doesn't matter which domain is defined, sendmail always changes it to "user at domain-b . dom". Here is excerpt from a logfile:
Jul 14 10:59:16 server sendmail[19537]: p6E7xGt3019537: from=user at domain-a . dom, size=491, class=0, nrcpts=1, msgid=<1310630356.19535 at domain-a . dom>, relay=loggedinuser at localhost
Jul 14 10:59:17 server sendmail[19538]: STARTTLS=server, relay=localhost. localdomain [127. 0.0.1], version=TLSv1/SSLv3, verify=NOT, cipher=DHE-RSA-AES256-SHA, bits=256/256
Jul 14 10:59:17 server sendmail[19537]: STARTTLS=client, relay=[127.0. 0.1], version=TLSv1/SSLv3, verify=FAIL, cipher=DHE-RSA-AES256-SHA, bits=256/256
Jul 14 10:59:17 server sendmail[19538]: p6E7xG06019538: from=<user at domain-b . dom>, size=607, class=0, nrcpts=1, msgid=<1310630356.19535 at domain-a . dom>, proto=ESMTP, daemon=MTA, relay=localhost .localdomain [127.0 .0.1]
Jul 14 10:59:18 server sendmail[19537]: p6E7xGt3019537: to=recepient at domain-c . dom, ctladdr=user at domain-a . dom (1005/100), delay=00:00:02, xdelay=00:00:02, mailer=relay, pri=30491, relay=[127. 0.0 .1] [127. 0. 0.1], dsn=2.0.0, stat=Sent (p6E7xG06019538 Message accepted for delivery)
Jul 14 10:59:18 server sendmail[19540]: STARTTLS=client, relay=smtp3. domain-c. dom., version=TLSv1/SSLv3, verify=FAIL, cipher=DHE-RSA-AES256-SHA, bits=256/256
Jul 14 10:59:18 server sendmail[19540]: p6E7xG06019538: to=<recepient at domain-c. dom>, ctladdr=<user at domain-b . dom> (1005/100), delay=00:00:01, xdelay=00:00:00, mailer=esmtp, pri=120607, relay=smtp3. domain-c. dom. [103. 50. 9.7], dsn=2.0.0, stat=Sent (Ok: queued as 2117414003)

there is too much info for one message and i don't understand where is the bottleneck? i understand that it's my knowledge, but anyway i need to find the place to change.
2. I defined virtusers to mail outside the server (gmail . com) but it does not work.

Please advice me, what to do to fix it. Please do not send guesses, only questions or answers.