Author: Bill Hacker Date: To: exim-users Subject: Re: [exim] Very long delay after RCPT
Ben Giddings wrote:
> It looks like I solved the problem. It was actually a DNS issue, rather
> than an exim issue. Exim was trying to resolve some hosts, was unable
> to do so, and bailed out after a while.
>
> I used Tony Finch's suggestion and ran Exim in debugging mode and
> watched what happened. I ran it as
>
> exim4 -bd -q30m -d
>
> I know that -bd tries to background it and -d overrides that an
> foregrounds it, but I wanted to use nearly the same configuration that
> gets used when I ran it from init.d
>
> So, I saw the DNS failures and figured that was the problem.
>
> One question though: does exim cache the results of the DNS lookups it
> does? From scanning what was happening, it looked like it was trying to
> resolv all the hosts in local_domains etc. multiple times. I hope it
> isn't trying to look up that unchanging list every single time an
> incoming email arrives. That seems pretty inefficient, if it is the case.
>
> Anyhow, looks like the problem is solved. Thanks!
>
> Ben
>
IIUIC, it does cache DNS (and other) lookups - unless running in a
manual test or debug mode, where it would not ordinarily be useful,
practical, or desireable to do so.
