I'm running a small LAN with two dual boot Linux/Win0.95 and a Linux
gateway running kernel 2.2.9 and ipchains 1.3.8 for firewalling and
masquerading (no proxies). Dial-on-demand connections via ISDN are made
with ipppd 2.2pl10.
After a couple of days there is a noticable slowdown with certain
services, especially DNS, but also POP3, NNTP and telnet. I don't know,
if it's caused by the gateway's uptime or by the number of connections
made, though. After reboot, everything is fast again for a while...
I guess, this slowdown is caused by high latency times, not lack of
bandwidth (hope you understand what i mean, sorry for any bad english).
With 2.0.36 and ipfwadm, there were no such problems, but I used ipfwadm
only for masquerading but no firewalling at all (gotten paranoid:) ).
Furthermore, I'd like to run a caching-only nameserver on my gateway
(ISP's nameserver as forwarder in /etc/named.boot, nothing else). However,
forwarded DNS querys seem to be sent over UDP, not TCP, which bites
ip_dynaddr, is this correct? Or, in other words, in which cases is
either UDP/TCP used for DNS?
Any solutions/hints appreciated, TIA
(please Cc any follow-ups, I'm not a frequent reader)