Are the MX records cached ?

[Simon Waters]

Zorglub wrote:
> 
> My goal is to have a mail server running on a server that have a dynamic IP
> adresse. I've made a test during 1 week (IP adresse changes each 24 hours)
> and it seems to work but I not sure as I know nothing about some missed
> emails.

Since MX record point to A records, as long as your A record has
a suitable TTL, it doesn't matter how long, or if the MX record
is cached.

So your question is more what TTL should I set for the A record.