Logging the connections

[kokencisco]

Hi,

I want know a way to log any communication between one interface (on a cisco 1721) and any destination. I know that I can do this with debug command but I know that this busy a lot my router.

Any idea?

[thisisshanky]

You can put an access-list on each interface and put the log keyword at the end, and each time packets match that, a log is generated on the console, which you can log it to a syslog server.

Make sure the acl doesnt deny the interesting traffic that you want to pass through the router.

Or else create an acl for the interesting traffic you are looking for and use it with the debug command.

debug ip packet detailed . This will reduce the amount of traffic you see because its restricted to only those traffic matched by the acl.

Or else,

Enable ip route-cache flow under each interface and use the command, show ip cache flow to see detailed info about traffic passing through that interface. Note that this command outputs port numbers in Hex, so you will need a calculator (scientific) - handy.

HTH