Serious error in FAQ for Linksys WRT54G/GL/GS routers

[kubanczyk]

In answer "Special note for users with Linksys WRT54G/GL/GS routers, there are severe problems with them when running any P2P app (read for fix)" I've found following fragment, which is outdated and misleads a lot of people now.

---------------- FAQ ANSWER WHICH I BELIEVE IS WRONG ------------------------

(See http://www.utorrent.com/faq.php#Special_note_for_users_with_Linksys_WRT54G_GL_GS_routers )

The following instructions are for DD-WRT only

Do not use the web interface method as it cuts off part of the commands.

Enable SSH (Admin, Services) as we are going to use the NVRAM method @ http://wrt-wiki.bsr-clan.de/index.php?title=Startup_Scripts#NVRAM_Method

Login to the router with an SSH client (root/your password).

Put the following commands into the SSH client.

~ # nvram set rc_startup="

> echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

> echo 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses

> echo '600 1800 120 60 120 120 10 60 30 120' > /proc/sys/net/ipv4/ip_conntrack_tcp_timeouts

> "

~ # nvram commit

~ # reboot

The system is going down NOW !!

Sending SIGTERM to all processes.

Note the ' instead of " on the third command line. Using " on the third command line closes the set command (as on last line), meaning that the last command will get cut off prematurely.

Make sure your "Maximum Ports" is set to 4096 on the Management page.

You can check the settings worked by logging in via SSH and viewing the contents of each file as below or using the "nvram get rc_startup" command.

~ # more /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses

1

Enjoy instant µTorrent speed increase from pretty much zero on each torrent to full speed!

Thanks frankw for the instructions for DD-WRT

---------------- WHY IS IT WRONG ------------------------

This solution works only on very old firmwares (it does *nothing* on DD-WRT v23 SP2) and only for TCP traffic, not for UDP.

Starting from kernel 2.4.23 file /proc/sys/net/ipv4/ip_conntrack_tcp_timeouts is ignored and proper one is in /proc/sys/net/ipv4/netfilter/.

You also can & should use web interface to change timeouts.

Even on older firmwares above solution doesn't help, since most Linksys hangups are caused by uTorrent DHT which sends thousands of UDP packets when using only hundreds of TCP connections at a time.

---------------- WHAT IS PROPER VERSION ------------------------

The following instructions are for DD-WRT v23 or later only

* Enter following values at 'Web-Admin -> Administration -> Management -> IP Filter Settings'

* Maximum Ports: 4096

* TCP Timeout (s): 300 (decrease if you have many TCP connections)

* UDP Timeout (s): 300 (decrease if you have many UDP connections)

* Save Settings and then Reboot Router

* This causes your inactive connections to be dropped after 300 seconds.

* For detailed explanation see http://www.dd-wrt.com/wiki/index.php/Router_Slowdown

regards,

Kubanczyk