MRTG when the client is offline

[Narayan]

When i monitor a snmp value with MRTG it all works fine. When the device that is beeing monitored goes offline mrtg just takes the last value and draws a flat graph. Does anyone know how to prevent this?

[Alex Atkin UK]

I believe the options would be:

Options[_]: unknaszero,withzeroes

The manual states:

unknaszero
Log unknown data as zero instead of the default behaviour of repeating the last value seen. Be careful with this, often a flat line in the graph is much more obvious than a line at 0.

withzeroes
Normally we ignore all values which are zero when calculating the average transfer rate on a line. If this is not desirable use this option.