dnsserver: Ports used for DNS traffic?

What port numbers does dnsserver (Squid v2.2S5) use for DNS traffic and
can they be configured?

For security resaons, I run BIND (v8.2.2) such that it exclusively uses
port 53 for all DNS traffic across my firewall (ipchains on a RedHat
v6.0 system). This scheme has been working great.

Now I've installed Squid and find that it attempts to use high port
numbers to communicate with the nameservers found in my
/etc/resolv.conf. The system log accurately shows the denial of access
to these port numbers.

This is a fragment of my /etc/resolv.conf:

nameserver 127.0.0.1
nameserver 24.4.162.33
nameserver 24.4.162.34

I assume that Squid is working only because it has unhindered access to
the ports on the 127.0.0.1 interface. The packets sent to the 2 other
addresses are simply dropped per the firewall rules. (The packet
destination is port 53, which is fine, but the *source* is not 53, which
is considered a no-no.)

I am aware the I can specify the interfaces to use (via the Squid
dns_nameservers param) rather than letting Squid parse my
/etc/resolv.conf, but is that the appropriate course of action? I'm OK
with Squid using the non-localhost nameservers; it's the ports other
than 53 that I want to avoid.

Any thoughts on this? Thank you.
Received on Sat Nov 20 1999 - 22:14:06 MST