[squid-users] SQUID PROXY ERRORS - SUPPORT

[Alex Rousskov]

On 4/7/23 07:00, Alessio Ballarini (External) wrote:

> - The TCP connections work inconsistently: sometimes they work (200) and 
> sometimes they do not (503).

> Specifically in the access.log of the Squid we registered these 503 erros:
> 
> 1680672739.134 59768 172.29.7.148 NONE/503 0 CONNECT 195.75.144.10:22 - HIER_NONE/- -
> 1680681044.960 60450 172.29.7.148 NONE/503 0 CONNECT appbpe.pellegrinicard.it:443 - HIER_NONE/- -

> We tried to debug the log of the squid, and we found that this error is 
> a "generic" application error that could depend on several factors.

Your conclusion is essentially correct -- many things may trigger an 
HTTP 503 error. To know what causes these particular errors (without 
guessing), one needs more information.

In modern Squids, using a custom logformat directive to log 
%err_code/%err_detail may help detail the error further in some cases. 
In all Squids, looking at the Squid error response itself (including its 
HTTP headers) may help detail the error further. You may want to share 
those details with the list.

Alternatively, if you can reproduce the error fairly easily, analyzing 
cache.log with debug_options set to ALL,9 can often determine the cause. 
If you go this route, please do not post huge logs to the list, but 
share a link to a compressed cache.log file instead. More hints at
https://wiki.squid-cache.org/SquidFaq/BugReporting#debugging-a-single-transaction


HTH,

Alex.