[squid-users] IPv6 TPROXY and ICMP Messages

Amos Jeffries squid3 at treenet.co.nz
Sat Sep 30 02:37:47 UTC 2017

On 30/09/17 10:56, Troy Telford wrote:
> I’m fairly sure that the firewall is configured to pass the ICMPv6 
> messages from any interface to any interface - Clients inside the 
> network are definitely seeing “packet too big” messages.
> So is there something in Squid which could be causing my path MTU 
> issues? Is there anything i can do to eliminate Squid as a source of error?

Squid just schedules data for TCP to deliver and lets the OS handle the 
details. Sounds to me like your TCP stack is not handling those ICMP MTU 
responses correctly.

IIRC the kernel versions 2.6.32-2.6.36 were found to have issues with 
their ICMP. But those got resolved.


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