Technical Tip: How to do a sniffer/packet capture by network as a filter

[pginete]

Description
This article describes how to do a sniffer using a network as filter.

Solution
Sniff is a useful command when debugging routing problems.

To do a sniff, follow the syntax below:

# diagnose sniffer packet <interface> <'filter'> <level> <count> <tsformat>

Example of network as a filter:

First filter: Sniff from two networks.

# diagnose sniffer packet any ‘net 1.1.1.0/24 and net 2.2.2.0/24’ 4 0 l

Second filter: Sniff from one source network to destination network.

# diagnose sniffer packet any ‘src net 1.1.1.0/24 and dst net 2.2.2.0/24’ 4 0 l

Third filter: Sniff from one source network doing a ping of destination network.

# diagnose sniffer packet any ‘src net 1.1.1.0/24 and dst net 2.2.2.0/24 and icmp’ 4 0 l