On 3/12/2008, at 2:19 PM, Subba Rao wrote:
Hello,
I want to collect data on a network and map the data flow and system/ port traffic. There are 2 scenarios of data collection here. The first is to collect IP traffic only. In this method I do not want the data portion of the IP packet (need IP address, source/ destination ports etc).
The second is to collect traffic that will show all the routing protocols (non-IP) used on this network. Today while collecting the data, I saw several HSRP packets. I don't know what portion of the packet is sufficient to capture for this purpose.
I used the "-s 0" option on tcpdump which captures the whole packet. That is making the dump file large. Any help with the filters is appreciated to capture the non-data portion of the packets.
Thank you in advance.
I strongly recommend having a look through this to find out what rules you want (ie. plain English): http://www.networksorcery.com/enp/default1002.htm Then, go about mapping them in to tcpdump/pcap/bpf/whatever filter format, a quick Google suggests this as a good resource: http://www.whitehats.ca/main/members/Malik/malik_tcpdump_filters/malik_tcpdu... You might also consider using netflow instead of tcpdump, there are lots of tools available for processing netflow data in ways that are useful to network operators. -- Nathan Ward