I use the same thread than the one for satellite links, since the problem
is similar.
We have our mail server, we have other 2 secondary server used in the
event that the first one is down for maintenance or other problem (the
more common is having a dos attack filling the disk, althought it is 17GB
it has filled four times this year)
The third one is the most useful, since it has an external-world
connenction on a different cable, with a different ISP, so it is quite
unlikely (but has occurred only once in 4 years, for less than two
hours) that both links are out.
SO in effet the MX10 is the main, the 13 is the secondary in case of the
first one being offline, the 17 one should come on hand if the main link
should be out, usually this occours about three times a month, for
period between 30' and 48 hours :( ,
(all three ones are connected directly on a "backplane" switch(.
I have noted that many messages with random addresses are sent the the
higher MX, that is the third machine. Since this cannot know anything
about the main one [addresses can be validated on the fly, so until you
try delivery you cannot know if it is valid or not] it must accept an
later bounce back.
Mi ides should be to redirect the port 25 of mx17 top the port 25 of mx10,
Using this arrangement calling either first or last mail exchanger would
end in connecting to the same computer, only using different connections
(more or less as having a dueal hosted main server)
Wpuld this work ?
there is the risk that some sender try on MX10 , have it busy, then
instead of going to MX13 go directly to MX17 that since is a rerouted to
MX10 probably would refuse again ?
