Re: ICP Port

From: Henrik Nordstrom <>
Date: Thu, 16 Jul 1998 22:37:18 +0200

Chris Galanos wrote:

> I don't think I am totally understanding the concept of ICP.
> Obviously I want it to make UDP requests to both of the parents to
> see which one is fastest, yet I want it to rely on one of the parents
> if the other goes down. In other worlds say I have:
> cache_host parent 8080 0

This setting (ICP port 0) does not work unless you use
single_parend_bypass on
or add the no-query keyword (which does not work reliably in 1.1.X
possibly including 1.1.22)

If you want Squid to check if the parents are alive then the parents
need to have at least simple TCP services installed (UDP echo), and you
can then configure the parents in Squid to use ICP port 7 (UDP echo).

If the parents support ICP then configure Squid with their ICP ports.

The key issue is that you can't use UDP queries unless there is someone
who listens to them. To support a approximation of ICP on non-ICP
servers Squid supports the use of the UCP echo port to measure if the
machine is alive and connected.

Henrik Nordström
Sparetime Squid Hacker
Received on Thu Jul 16 1998 - 13:52:14 MDT

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