Preventing AIM Disconnects with DD-WRT

If you have a Linksys WRT54G router, then you may be familiar with the DD-WRT firmware. Or, in case not, here's a quick recap — the Linksys WRT54G runs Linux and, by its GPL nature, they’ve released the source code for their firmware; building upon that, many others have created firmwares with extra features.

The real deal is what the WRT54G can do, with the right replacement firmware, that you’d only expect to find on a commercial-grade router costing several times as much.

You could use the WRT54G as a repeater or a bridge. Create a wireless distribution system (WDS) or a mesh network. Run a VPN server. Or a VoIP server. Or a managed hotspot with a RADIUS server. Manage bandwidth use per protocol. Control traffic shaping. Support IPv6. Boost antenna power. Remotely access router logs. Operate the router as a miniature low-power PC, running a variety of Linux applications.

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In any case, I’ve been running DD-WRT for several months now and it’s been working great. My favorite feature may be the static DHCP set up — you can define a MAC address for which it will alway receive the same ip address. (That can be pretty handy to ensure that port forwarding always works as intended.)

While the firmware is well coded, there are some circumstances where the stock configuration runs into trouble. The first major one is Bittorrent; apparently, the high number of connections can overwhelm its poor little mind. However, if you set “Maximum Ports” to 4096 and both “TCP Timeout” and “UDP Timeout” to “120 seconds”, Bittorrent should be back on track. (All of these options are under Administration → Management.)

However, I found that AIM still became disconnected from time to time. Well, to say that it was “disconnected” probably isn’t fair; rather, it would occasionally have a connection blip where it’d disconnect and then immediately reconnect. It was mostly only an annoyance, but I had wanted to get to the bottom of it.

As a first step, I installed the beta of v23 SP1 as I had recalled reading on the forums that a few connection-related bugs had been squashed since the v23 release. I followed the upgrade steps on the wiki, but I’d still occasionally see AIM disconnects.

After some further reading on the forums, though I read a recommendation for setting both “TCP Timeout” and “UDP Timeout” to “600 seconds” to remedy AIM disconnects. I gave it a shot and, sure enough, it worked. I’ve not had any AIM disconnects since then — and Bittorrent has continued working fine as well :).