Is it possible to exclude a constant value from a counter?

[Mcleod]

Hi,

I am running snmpd on various linux hosts, and using cacti to poll interface statistics from each.

The problem I have is that servers that are sitting there doing absolutely nothing, are reporting an average incoming usage of around 35Kbit/s - I suspect this is to do with the poling of snmp statistics.

What I need to do, is be able to remove this traffic from the reports, (prior traffic is fine, just a fix from now onward would be fine). I was thinking that if I could find the peice of code that pulls the ifInOctet values than I could remove a constant figure from every polling input.

Such as, fetch the ifInOctet value every five minutes then subtract 35 * 8 * 60 * 5 ... from that value.

Can anyone suggest how I could go about this?

The traffic might seem insignificant to most but it is important to me to have it excluded.

Any advise would be greatly appreciated

Thank you

[Mcleod]

Hi again,

Sorry I no longer feel that snmp or cacti is to blame, attempting to work out what it could possibly be... constant stream of 40Kbit/s inbound but nothing outbound...

[gandalf]

In this situation, I'd prefer to do a tcpdump on that machine.
Reinhard