Re: cache peer questions

Oskar Pearson wrote:

> You should turn prefer_direct off if you have a firewall as a parent.

No. If you are firewalled then you should use never_direct which is much
stronger than prefer_direct.

> Nobody has ever explained fully what prefer_direct's interaction with
> a default parent is

Squid 2.2 implementation of non-ICP peers is basically braindead, and it
will default to only use alive ICP peers.

"prefer_direct off" will make it try to use non-ICP parents for requests
where it could not find a ICP peer. It will however do so for close to
all requests, even such requests where it would normally bypass ICP
peers. It will however still go direct on some types of requests or if
it fails to connect to the parent(s).

Non-ICP parents are selected in this order:
    default
    round-robin
    first up
    any (??)

If you have multiple default parents then it will select the first up
among them.

never_direct forces Squid to not ever try to go direct for matching
requests. It will always try to find a alive peer to forward the request
to.

--
Henrik Nordstrom
Spare time Squid hacker