General SMTP/MTA Question

[Evan Klitzke]

I am thinking about running an MTA on my home server. At home I am
connected to the Internet through a regular DSL account, so my IP
address is not static, and every few days when I get a new DHCP lease
and the DNS record for my domain has to be updated, which takes about
half an hour. In the meantime, the DNS record for my domain will point
to the old IP address. This isn't really a problem with my HTTP server,
because it is mostly for personal use, so when it isn't reachable it
isn't a big problem. However, I would be concerned about losing email if
an MTA tried to pass mail to me and found that they couldn't reach my IP
address, or that port 25 was blocked on that address.

How resistant are most MTAs to this kind of failure? In other words, how
realistic is it to expect that someone else's MTA trying to deliver mail
to mine will hold it in its mail queue and retry sending long enough for
it to get through? Will this actually happen, or would a typical MTA
just drop the message from its mail queue if the domain wasn't reachable
(or not accepting connections on port 25)? I am hoping some veteran
sysadmins on the list will have enough experience to know what to
expect.

Thanks a lot,
Evan Klitzke