Re: [exim] Email DNS Issue

Pete McEvoy wrote:
> On Sat, Mar 15, 2008 at 10:11:08AM +0000, W B Hacker wrote:
>> Pete McEvoy wrote:
>>> On Sat, Mar 15, 2008 at 04:34:39AM +0000, W B Hacker wrote:
>>>> If you have significant traffic from a specific host that commonly fails
>>>> or times-out on DNS lookup, AND you otherwise feel you can 'trust' it,
>>>> you can manually enter it in /etc/hosts, which is (normally) checked
>>>> before making a (remote) DNS query.
>>> This isnt the case on any of the linux boxes I run exim on, exim does a
>>> MX lookup first.
>> That part is expected.
>
> Doesnt that contradict your previous statement?

"DOTS" (Depends On The Situation)

E.G. - used in Win NT (hosts.sam altered), Warp 3 & 4, FreeBSD 4 thru 8,
OpenBSD, OS X.... yadda ...

I've never tried it in Linux...

>
>>> In fact I cant get it to look in /etc/hosts at all.
>> Not a Linux mavin here, but what does 'route -n show' produce?
>
> The help for route, the version of route I have doesnt seem to like
> `show' , route -n prints the routing table, which isnt too exotic on any
> of my boxes, fairly standard stuff. Where does that come into it?

AFAIK (again 'DOTS') whatever serves a given environment for the route
daemon may look externally first, internally first, or be configurable
to do one or the other.

Most of what I use in a given day looks locally first, e.g. mapping
ads.doubleclick~, google-anal~ and similar vermin to localhost in
/etc/hosts intercepts the callouts to DNS and saves dld'ing garbage,
wasting time logging the sweat-stains, etc.

> Not to
> be adversarial, you seem a nice chap and you've answered questions from
> me in the past, albeit in a meta syntactic way that I found hard to
> grasp at the time but have since learned to be sound.
>

LOL ..

guilty as charged...

> I suspect Im still feeling the effects of last nights binge drinking, so
> feel free to hit me with the cluebat if Im missing something obvious.
>

Only if you were putting dirty water - frozen or otherwise - into good
malt - but that's what leads to hangovers, so is its own punishment..

> Cheers
>

'missing' is that *hopefully* the OS handles routes and does some
caching ahead of Exim. I could be wrong - and seem to be - for Linux.

At least OpenBSD allows setting the priority - just happened to be
working in that very area last night.

FreeBSD and Linux may do as well - I've just not needed to look.

Bill