DNS query burst slows down LAN
Hi,
Lately I installed a DNS server for local hostnames. I'm running a linux server (Debian) at home, and I want the DNS of my server to resolve locally within my LAN. This is my network: internet - modem/router/dhcp - multiple computers (including linux server) The modem dhcp configuration contains a dns server IP of my local linux server. Everything works fine, but from time to time the DNS server generates a query burst and tries to resolve a.root-servers.net until z.root-servers.net and much more DNS names. The result of this burst is that my modem cannot handle the amount of connections and refuses any new connections. The burst is about a few minutes long, after that there are new connections available in the modem. It sometimes also causes connection drop and usually a high latency. I already tried to set serial-query-rate to 1. But with no effect. This is my named.conf.options: Code:
options { Code:
// This is the primary configuration file for the BIND DNS server named. Code:
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) Code:
# The following lines are desirable for IPv6 capable hosts |
Quote:
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/etc/hosts ?.
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I already have a forwarder specified:
Code:
forwarders { |
That's private IP addr, ie inside your LAN. Probably doesn't have that much of the internet addresses cached. Certainly not as much as your ISP will have.
Also, if this is happening regularly, sounds like one (or more) of the time-outs specified here http://www.linuxtopia.org/online_boo...-zone-examples is set too short, probably the 'refresh' entry. |
Quote:
I'll try to put the DNS servers from my ISP instead. And hopefully the requests will go over one line instead of multiple lines. But I still don't understand why it's caching the internet addresses like a.root-servers.net. I can't imagine there's any program that will resolve addresses like that. |
It did not help, the DNS server is still bursting queries time to time, resulting in massive package drops and refused connections.
I also lost connection to some irc servers for about 5 minutes. Do you think it can be solved by writing an expect script that forces to delete the dns udp connections in the modem? |
How to remove query burst from dns source code
Does someone know how to remove the DNS query burst from the source code?
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