bind refresh?

carboncopy · 12-15-2004, 02:18 AM

Hi!

I wonder how do I control a caching DNS refresh period? And how do I find out when will it purge or refresh records?

Thanks.

peter_robb · 12-15-2004, 03:43 AM

It uses the TTL value from the dns records it finds..

The default is usually 3 days, but it can be adjusted..
There are 6 values..

See http://langfeldt.net/DNS-HOWTO/BIND-...O-7.html#ss7.5

carboncopy · 12-16-2004, 03:15 AM

Thanks for the pointer. Will look into it.

Another question on caching DNS.

Let's say I am behind a firewall. And the only DNS I am able to access to is the one in the network. Not those main DNS in the Internet.

Where do I put the information? /var/named/named.local or /var/named/named.ca or whatelse? And how should it look like?

peter_robb · 12-16-2004, 07:50 AM

I'm not sure I understand what you are trying to do..

To add dns records manually to the caching dns server in your network?

To add records for just one pc to use (Linux or M$ ?)

To stop the caching dns server from looking into the internet for a record?

Cedrik · 12-16-2004, 09:24 AM

For the machine client you just put the LAN nameserver IP in /etc/resolv.conf

carboncopy · 12-16-2004, 07:32 PM

Quote:

Originally posted by peter_robb

To stop the caching dns server from looking into the internet for a record?

YES!

Ask it to look at the LAN DNS instead.

carboncopy · 12-16-2004, 07:34 PM

Quote:

Originally posted by Cedrik
For the machine client you just put the LAN nameserver IP in /etc/resolv.conf

I do not want to depend on the LAN DNS as it is VERY VERY fragile and unstable. I want to have my own DNS on my machine.

cidrolin · 12-17-2004, 01:44 AM

the question is : will the FW allow dns requests to reach the outside world when they originate from your machine ? If I had set up this FW it wouldn't...

peter_robb · 12-17-2004, 04:20 AM

Even if you have your own caching nameserver on your pc, eg dnsmasq,
it will still only be able to talk to your LAN's dns server..

It will be faster for some cached requests but will have to talk to the LAN server to get fresh records..
You can enter records manually as well ...