[squid-users] Squid4 ICAP connection handling

[Alex Rousskov]

On 04/09/2018 06:03 AM, Peter Viskup wrote:
> Running Squid 4.0.23 the ICAP connections getting "frozen".
> 
> proxy:~ $ netstat -ntpa| grep 40620
> tcp   920144      0 127.0.0.1:40620         127.0.0.1:1344
> ESTABLISHED 1165/(squid-1)
> tcp        0 2744857 127.0.0.1:1344          127.0.0.1:40620
> ESTABLISHED 1211/esets_icap
> 
> # after ICAP service restart
> proxy:~ $ netstat -ntpa| grep 40620
> tcp   920144      0 127.0.0.1:40620         127.0.0.1:1344
> ESTABLISHED 1165/(squid-1)
> tcp        0 2744858 127.0.0.1:1344          127.0.0.1:40620
> FIN_WAIT1   -
> 
> # later on - squid still keep the connection open
> proxy:~ $ netstat -ntpa| grep 40620
> tcp   920144      0 127.0.0.1:40620         127.0.0.1:1344
> ESTABLISHED 1165/(squid-1)

> How the ICAP connections are handled?

The question is too general to give a brief useful answer.


> Was there any change in the code? 

Yes, a lot of code has changed between Squid v3 and v4, including some
ICAP-related changes.


> We didn't experienced this with Squid3.5 before.

Is there an HTTP transaction associated with (e.g., waiting for) that
stuck ICAP connection?

Can you reproduce this problem with a single HTTP transaction? Or does
it take many transactions to get Squid into this state? If you can
easily reproduce, I recommend filing a bug report with an ALL,9 trace of
the problematic transaction attached.

Alex.