How to have open more than 65k concurrent connections?

Thu Oct 14 16:53:21 UTC 2010

An incoming connection chews up an file descripter but does not require
an ephemeral port.

You can trivially have more that 65k incoming connections on a linux
box, but you've only got 64511 ports per ip  on the box, to use for
outgoing connections.

I've seen boxes supporting more than a million connections with tuning
in the course of normal operation.

On 10/14/10 9:03 AM, johndole at hush.ai wrote:
> Hi,
> 
> I am somewhat new to networking. I have interest in running a 
> Bittorrent tracker. I ran one for a bit, and my one Linux box 
> running Opentracker gets overloaded. My connection is good, and 
> most of it isn't being used. Just a lot of people connect, and use 
> up all the 65k "free connections". I tried messing with the 
> sysctls, but it didn't help too much (and just degraded the 
> connection quality for everyone). It is not a malicious attack 
> either as there is only a few connections per IP and they are 
> sending proper Bittorrent tracker requests...
> 
> So what can I do? How can I have have open more than 65k concurrent 
> connections on standard GNU/Linux?
> 
> Thanks for any ideas and suggestions.
> 
> -John
> 
> 