topic NAT tuning in Operating System - Linux

NAT tuning

Nils_9 — Thu, 21 Sep 2006 03:28:50 GMT

Hi,

I've got 2 computers acting as NAT gateway and running Fedora Core 5. For some VOIP tests, I need to tune some parameters, such as the delay of connexion closing when there is no activity.

I know these parameters are located in /proc/sys/net/ipv4/netfilter/ (a funny thing is the fact I don't have this directory on my desktop computer running Mandriva 2006), but I don't know the meaning of theses parameters. Does anyone know what they all mean? Or at least what I need to modify?

Thanks in advance,

Nils

Re: NAT tuning

Al Licause — Thu, 21 Sep 2006 08:14:26 GMT

Don't know what would be contained in the netfilter subdirectory but I think most of the parameters you're looking for are in the ipv4 directory.

I would suggest purchasing a copy of TCP/IP Illustrated Volume 1 by Stevens. It's one of the better books documenting network parameters.

Re: NAT tuning

Matti_Kurkela — Sat, 23 Sep 2006 07:10:21 GMT

The documentation for variables in /proc/sys/* comes with any Linux kernel source package. Many distributions also offer a package named "kernel-docs-" (or something similar) that contains only the documentation.

The file you need is /Documentation/networking/ip-sysctl.txt.

I don't have a computer with Fedora available just now, so you'll have to find out the exact name of the required source/documentation package in that distribution and the install location of the files in that package.

Re: NAT tuning

Nils_9 — Sat, 23 Sep 2006 07:33:40 GMT

Hi,

actually the book didn't help me. I looked at the documentation of the kernel in www.kernelhq.com, but it never makes any reference about theses values.

I found something in Google Groups. I won't put the url here unless you speak french, but as I understood, the values I have to modify for my VOIP tests are, in TCP : ip_conntrack_tcp_timeout_last_ack and ip_conntrack_tcp_timeout_fin_wait

in UDP, I have to modify ip_conntrack_udp_timeout.

Thanks,

Nils

Re: NAT tuning

timmy2006 — Wed, 08 Nov 2006 01:22:02 GMT

sysctl -a | egrep "udp|ip"

vi /etc/sysctl.conf