Re: No ICP Replies

From: Dancer <>
Date: Thu, 04 Dec 1997 20:06:08 +1000

Rainer Klier wrote:

> Hi there,
> we are working with squid 1.1.16 and the only parentproxy we can contact
> is a netscape 2.53 proxy. Our squid.conf says:
> cache_host parent 81 7 weight=10 no-query default
> As far as I know, no ICP replies should be sent to this proxy. But
> often we get: No ICP replies an the host is beyond the firewall.
> The logfile says something like:
> 881217134.637 45 ERR_CANNOT_FETCH/400 966 GET - NO_DIRECT_FAIL/ -
> Are there any ICP requests sent to this parentproxy ? In case yes: what
> do I have to do, to avoid this problem ? In fact the parentproxy is

In theory no. If you have single_parent_bypass on then _absolutely_ not.

> never down in this time we do get those messages (a telnet 81
> works without probs). Another proxyadmin said, that an upgrade to 1.1.18
> wouldn't help.

Look in your cache_log for an entry like 'TCP connection failed to'

That'll be your culprit. A connection is not getting opened properly, and Squid is marking the host as unreachable for several
minutes (during which it spits that particular error message). After a few minutes it tries to reestablish contact and
succeeds, and all goes back to normal. It's demoralising for the users.

I have a 1-byte patch to one source file that makes this go away, by ignoring the negative caching in this circumstance. It can
be cleaner. It _should_ be. I should have patched it so that it would only cheat if there was a single parent only.


In squid 1.1.17

neighbors.c, line 1148 it says: p->tcp_up=0;

Change it to: p->tcp_up=1;

And your problem will largely go away. The odd connection will fail, but they will never mark the host as unreachable.
You could _try_ recompiling with -DRETRY_CONNECT=1 but I suspect that that code is largely untried, and probably unsafe for a
production system. Duane? You'd know.

Good luck.


> Thanx in advance,
> Rainer
> --
> ______
> /| | Rainer Klier | Wahr sind auch die Erinnerungen, die wir mit
> / |__ | Thomas-Mann-Str. 6| uns tragen, die Traeume, die wir spinnen,
> | /__/| | 90763 Fuerth | und die Sehnsuechte, die uns treiben. Damit
> | | ||__| Germany | wollen wir uns bescheiden.
> | |__|/ / email : H.Spoerl
> |/______/
> URL :

Note to evil sorcerers and mad scientists: don't ever, ever summon powerful
demons or rip holes in the fabric of space and time. It's never a good idea.
ICQ UIN: 3225440
Received on Thu Dec 04 1997 - 02:11:52 MST

This archive was generated by hypermail pre-2.1.9 : Tue Dec 09 2003 - 16:37:50 MST