[Mimedefang] Using relay_is_blacklisted() or Sendmail dnsbl feature ?

[Ole Holm Nielsen]

John <john at jjgb.com> wrote

> Spamcop is not defunct, but maybe another one in your dnsbl is. Do a dig
> or nslookup on each host you use in you dnsbl in sendmail.mc and see 
> which
> one is not resolving. It definitely sounds like a dns time out issue 
> though...


Nope, I tested a number of RBLs that work perfectly with our other 
mailservers,
including rbl.fysik.dtu.dk which I run on a local server and which gives
sub-second responses.  I agree that it sounds like a DNS timeout 
problem, but
probably it's located in the glibc or Sendmail code, which is why I'm 
asking
if people have experience with Sendmail 8.12 on Redhat 7.2 or ES2.1.
I'd like to try Mimedefang's relay_is_blacklisted() for comparison,
if I could get an example of how to use it.

Ole Holm Nielsen
Department of Physics
Technical University of Denmark