Re: [squid-users] The requested URL could not be retrieved

ons 2006-05-03 klockan 13:41 -0700 skrev yves:

> So why can't I use squid that is a proxy as I have been told? And how?
> Back the the origin of this discussion....

Squid is a caching proxy for HTTP, not other protocols. Only HTTP
clients (mainly web browsers) can use Squid, and only for things which
can be wrapped as HTTP. (i.e. HTTP, HTTPS, FTP and Gopher).

Squid happily coexists with proxies for other protocols if
needed/desired. There is no conflict in running as many types of proxies
you like on the same server.

If all you are after is connection sharing then chances are that you
don't actually need a proxy but maybe would be better off using NAT. NAT
is simple, lighweight, works with most things, but isn't strictly by the
book for TCP/IP networking.. (bending the rules slightly). It's very
very common in small and home networks for sharing a Internet
connection. For example NAT is what all those small "broadband routers"
you can find in the nearest computer shop is mainly doing.

The Windows proxy you used is most likely a SOCKS kind of proxy (or
maybe a WinSOCKS proxy). SOCKS is a generic proxy method for TCP/IP and
is quite well supported by most clients. WinSOCKS is an extended variant
specifically tailored for transport level proxying of the networking
operations of Windows applications.

Difference between NAT and proxying is that NAT takes place at the
packet level by rewriting the packets as they travel to/from the
Internet, while proxies operate at the application protocol level (with
the exception of SOCKS which can be viewed as sitting somewhere
inbetween more like at the transport layer.. but lets not complicate
things more than needed)

As already mentioned proxies exists in two kinds:

a) Application specific proxies like Squid who have deep knowledge of
the specific protocol (i.e. HTTP) and adds extra features beyond simple
sharing of the Internet connections.

b) Generic protocol neutral SOCKS kind of proxies. Usually does very
little besides just shuffling traffic and maybe a bit of access control
on who may use the proxy.

And then the third option is

c) Or you could use NAT, without any proxy.

Regards
Henrik