simple load-distribution setup - but weird behaviour

simple load-distribution setup - but weird behaviour

[Per Jessen]

Hi,

we're using iptables in a fairly primitive load-distribution setup - 

iptables -t nat -A OUTPUT -d 192.168.3.200 -j DNAT --to
192.168.3.101-192.168.3.108

All traffic originates on the local machine. It's been working fine for
quite a while, but today I noticed that only 7 of the 8 machines in the
cluster are being distributed to - 101,102,104,105,106,107,108 but not 103. 

There isn't an awful lot of traffic, perhaps 2-3 msgs/min. Kernel is 2.4.24. 
I tried telnet'ing to 103 (port 10025) which worked fine - and following
that 103 was suddenly also being distributed to automagically.

Is there a way of determining why 103 was not being distributed to? Or when
if this happens again, what can/should I look at? 


cheers
/Per Jessen, Zurich

Re: simple load-distribution setup - but weird behaviour

[Per Jessen]

Per Jessen wrote:

> iptables -t nat -A OUTPUT -d 192.168.3.200 -j DNAT --to
> 192.168.3.101-192.168.3.108
> 
> All traffic originates on the local machine. It's been working fine for
> quite a while, but today I noticed that only 7 of the 8 machines in the
> cluster are being distributed to - 101,102,104,105,106,107,108 but not
> 103.

I've just now seen this problem again - I had taken 2 nodes down for
maintenance, and although they're both back up and running, iptables is now
not distributing traffic to them. 

Any hints or suggestions?  I'm sure clearing the filtering tables will do
it, but I'd rather understand what's going on here. 


cheers,
Per Jessen, Zurich