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On Thu, Jul 24, 2003 at 11:51:42AM -0500, Fuzzy Fox wrote:
> Julian Eduardo de Anquin <[EMAIL PROTECTED]> wrote:
> >
> > I'm having some troubles in my network.  I have a masquerade server,
> > to provide internet access to my lan.  Spontaneously some computers in
> > the network cant access the internet, while others can.
> 
> This could indicate that your connection table is filling up.  If that
> happens, hosts that have an established connection can continue to use
> the net, but hosts trying to open new connections will fail.  Is that
> what you see?
> 
> Your best source of information is the firewall itself.  Login and check
> system logs, "dmesg" output, and see if anything suspicious shows up.
> 
> You can examine the connection table with
> 
>     cat /proc/net/ip_conntrack
> 
> You can just get a count of how many connections there are with
> 
>     cat /proc/net/ip_conntrack | wc -l
> 
> If the table is huge, you would need to examine it by hand to see what
> hosts and IP's are causing all the connections.

IIRC, the maximum number of connections is also set to a default value
based on the available memory in the system.  To see what it's set to:

   cat /proc/sys/net/ipv4/ip_conntrack_max

Which in my case is currently 30712 on my main firewall, 1024 on an old
486 I used to use, and 4096 on another firewall I maintain.  The new
system has significantly more memory than both the others (512 vs 64 &
16).

You can also increase this by echoing a larger number into it:

   echo "4096" > /proc/sys/net/ipv4/ip_conntrack_max

However be aware that doing so will increase the memory used.

-- 
Jamin W. Collins

Linux is not The Answer. Yes is the answer. Linux is The Question. - Neo
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