Re: dnscache and oversized answers

Thus said John Levine on 06 Oct 2008 10:55:12 -0000:

> One of my users noticed that MX lookups for xo.net were timing out.

Has  this been  reported to  XO? Granted  they may  not fix  it, but  it
doesn't hurt to point out their stupidity.

Failing that, why  not just take their highest preference  MX record and
put it into  your smtproutes file and  be done with it.  Sure, you won't
get any updates, but then their DNS is broken so what can they expect.

> The problem turns out to be that  XO's name servers are putting in too
> many additional section records and are returning oversized answers of
> about 540 bytes, which dnscache then throws away.

I assume this is because XO's  name servers aren't setting the truncated
bit?

Andy
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