Re: Squid sending UDP to port 7 of a remote server? Possible?

Chris Tilbury wrote:

> Hmm. Does this mean if you enable source_ping _and_ have ICMP
> support compiled in, squid doesn't send UDP echo packets? Or
> does it still send them?

I had to take yet another look in the sources to get a grip on when ICMP
and UDP source pings are sent..

If ICMP is compiled, then source_ping uses ICMP to ping the source, and
not UDP echo.

ICMP echo (if compiled) is used on
 * source_ping
 * ICP query with RTT option
 * ICP query and test_reachability is enabled in squid.conf

There seems to be some minor confusion in ICP query processing here. The
ICP cases should probably be anded together and test_reachability
documented in squid.conf.

If the functionality of source_ping is going to be kept is should be
rewritten to use RTT/hops limits based net_db (ICP uses net_db) to limit
the number of pings sent. There is no point in pinging the source on
every miss.

---
Henrik Nordström
Sparetime Squid Hacker