Re: DNS lookup failures

> Subject: DNS lookup failures
> From: Chris Fedde <cfedde@keota.uswmedia.com>

> It appears that squid ipcache only keeps one address per name.
> This is a problem when proxying to sites that have multiple A
> records. In the event that one of the addresses is unavailable and
> squid has cached that address it will continually return site
> unreachable even though a connection to the host is possible.
> This is a mis-feature.

I think there should be a TTL in the cache entry to delete
the fetched record afetr a certain amount of time ...

> Most DNS aware clients will try each address returned from DNS in
> succession. BIND implements a perfectly functional IP address
> cache that follows all the "right" rules.

This is called a load-balanced DNS ... (RRS)

> I'm thinking about ripping out the whole ipcache system and replacing
> it with a simple call to gethostbyname.

That would simply blow up the Squid proxy ! The ipcache system implements
a _non-blocking_ name<->ip resolution mechanism, but gethostbyname is a
blocking call ! Remember that Squid is a single-process program ... ;-)

Pierre-Yves
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Pierre-Yves KEREMBELLEC Phone # +33 1 46 12 67 50
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40, rue Gabriel Crie E-mail pyk@sv.vtcom.fr
92245 Malakoff Cedex, France WEBMaster / FTPMaster
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Received on Sat Aug 10 1996 - 01:12:00 MDT