Karl, That was exactly what I was looking for. Did the local-host-names changes; I already had the RELAY lines in access on the backup machine. Since the primary DNS is on the down IP address, I modified the secondary (slave) DNS which is one of my office boxes by adding a second MX line: my-host MX 99 temp.server.domain. <--dot at end and restarted that named. Its been quite a while and I'm not seeing any mail queueing, and I know there's mail that should be coming in on a regular basis. What else might I have missed? What can I use (nslookup, dig ? with what parameters) to see whether the MX lines are right? When I send a test email from an off-site machine, the sending sendmail log says "Connection timed out" and shows the down IP address. Dick At 03:52 PM 10/1/2003 -0400, you wrote:
on the backup RH mail box: add you domain to the backup /etc/mail/local-host-names and set it to relay in /etc/mail/access
type make in the /etc/mail/ directory and restart sendmail.
you can try testing it. send mail to your domian. also, could telnet to mailserver.com 25 and put SMTP comands to verify it is accepting mail for that domain.
when it is buffering the mail, it should show up in /var/spool/mail
if your home DSL is going to be down for some time, you might just want to bring the box into the office, and point the DNS directly at it, if you can.
On Wed, 1 Oct 2003, Richard Goodman wrote:
My home DSL has been down for over 48 hours and it appears that it will be down for several more days. (I spare you the gory details). I am concerned about losing mail coming into various domains at that site. That RH 7.3 machine runs mail/web/primary DNS for those domains.
I have modified the secondary DNS records for those domains (on a machine at my office - also on DSL) with an higher cost MX record pointing to a machine at the office also running RH 7.3 and sendmail, which I assume will pick up and queue the mail. The DNS TTLs are reasonably short, fortunately.
I've done this following O'Reilly/Sendmail book 2nd edition, but its not always crystal clear if you don't already understand it! Is there anything else I have to do on the backup machine (pointed to by the new MX records), particularly is there anything I have to do to its sendmail config files?
Any other pointers or "gotcha"s to this whole process?
Dick