Sorry for the confusion. Here is the configuration that I have: Accessible to the internet is a Fedora Cora 1 machine running sendmail for a particular domain. So, it has a MX record for that domain. Inside our firewall I have a Red Hat 7.3 machine that runs sendmail locally that has access out of the firewall on port 25. The 7.3 box just Whenever the 7.3 box sends mail out as root, its return address is root@xxxxxxxxxxxxxxxxxxxxxx The 7.3 is not in the same domain as the Fedora machine. The mail leaves the 7.3 box and gets to the Fedora machine. At the point where it hits the Fedora machine the return address is rewritten as the domain of the Fedora machine. In the sendmail.mc file here are the changes I have made: define(`confSMTP_LOGIN_MSG',`$j Sendmail; $b')dnl define(`confSMTP_LOGIN_MSG',`$j Sendmail; $b')dnl TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl define(`confCACERT_PATH',`/usr/share/ssl/certs') define(`confCACERT',`/usr/share/ssl/certs/ca-bundle.crt') define(`confSERVER_CERT',`/usr/share/ssl/certs/sendmail.pem') define(`confSERVER_KEY',`/usr/share/ssl/certs/sendmail.pem') DAEMON_OPTIONS(`Port=smtp, Name=MTA')dnl Hopefully I explained this a bit better. THanks! Dave >>> alexander.dalloz@xxxxxxxxxxxxxxxx 4/26/2004 2:07:00 PM >>> Am Mo, den 26.04.2004 schrieb David Benigni um 19:54: > I'm actually not using the SMART_HOST feature. Its seems all mail that > comes into the Fedora box rewrites the domain. I can post the relevant > configs if needed. Thanks! > > Dave Dave, sorry, but your initial mailing sounded like you are using the Fedora host as a smart host for the other Linux host. So what exactly did you mean by "However, I have another linux machine that sends mail out as root@xxxxxxxxxxxxxxxxxxxxx and when it passes through the Fedora box its rewriting the domain from localhost.localdomain to the hostname.domain of the Fedora box." With your todays reply I do not understand what that means. Is the Fedora machine the recipient's machine then? And yes, post your configuration files, at least what you did change. Alexander -- Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13 Fedora GNU/Linux Core 1 (Yarrow) on Athlon CPU kernel 2.4.22-1.2179.nptl Sirendipity 20:03:02 up 8 days, 2:48, load average: 0.31, 0.23, 0.19 [ ***** *'***** - gnothi seauton ] my life is a planetarium - and you are the stars