DNS query timeouts

Barry Margolin barmar at bbnplanet.com
Thu Jul 15 19:45:56 UTC 1999


In article <7mkht1$c4b$1 at oravannahka.Helsinki.FI>,
Tero A Kauppinen  <takauppi at cc.helsinki.fi> wrote:
>We are currently using FreeBSD 3.2 & Bind 8.1.2 and are 
>facing some problems when trying to resolve addresses. The setup we 
>have is as follows:
>
>   H -------- S ---------------- B -------- ( The Internet ) ---- X
> (host) (internal server)   (bastion host)                     (target host)
>
>If H tries to query the address of host X, the operation fails for the
>first time. The problem, as I understand it, is with timing, i.e. S 
>doesn't wait long enough for an answer from B. However, when the query 
>is repeated, S has already got an answer for its previous query, and 
>thus the answer can be found in the cache. 
>
>How can I increase the time S waits for an answer from B before
>returning an error to H?

I assume S is configured as a forwarding server, with:

   forwarders { <address of B>; }

The trick is to put B's address in there multiple times, i.e.

   forwarders { <address of B>; <address of B>; }

After S times out on the first address it will try again using the second
address.

This worked in BIND 4; I hope they haven't added duplicate detection in
BIND 8, thinking that it would be an optimization.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.


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