A records like MX?

[Martin F. Krafft]

also sprach Skeeve Stevens (on Tue, 14 Aug 2001 08:17:09AM +1000):
> I was wondering with Bind 9... or some other way to do this.
> 
> MX records can have a priority i.e. 
> 
> MX 10 mail1
> MX 20 mail2
> 
> Is this possible for A records?

the MX priorities are not a server feature, but rather a client
feature. in fact, the "10" and mail1 are all part of the answer of the
MX record, the server doesn't care a bit about it being 10. it's
postfix, or whatever else you use, which will try the lowest priority
first and only resort to the next one if the first one fails.

with HTTP, this is not implemented in the clients. therefore, you
can't really do it. however, i have a similar problem and i solve it
with the help of BIND9's dynamic update and another machine. this
other machine simply requests a page of the first webserver every 5
minutes or so, and if it goes down, it updates the A record for the
domain to point to the next server, and so on. only when the request
to the first server succeeds three times in a row, then does my script
automatically change the A record back to the first server. of course,
you need a relatively low ttl for that (i use 5 minutes).

martin;              (greetings from the heart of the sun.)
  \____ echo mailto: !#^."<*>"|tr "<*> mailto:" net at madduck
-- 
weekend, where are you?