topic Switch doing port scanning? in Network Security

Switch doing port scanning?

burleyman — Sun, 10 Mar 2019 11:14:48 GMT

I am seeing allot of ARP requests that looking like the switch is scanning our network and incrementing by one....like something has a virus. Here is what I am seeing in the switch....

Aug 12 19:12:54: IP ARP: sent req src 10.0.0.254 0021.1b83.0000,

dst 10.0.61.176 0000.0000.0000 Vlan10

Aug 12 19:12:55: IP ARP: sent req src 10.0.0.254 0021.1b83.0000,

dst 10.0.61.195 0000.0000.0000 Vlan10

Aug 12 19:12:56: IP ARP: sent req src 10.0.0.254 0021.1b83.0000,

dst 10.0.61.196 0000.0000.0000 Vlan10

Aug 12 19:12:56: IP ARP: sent req src 10.0.0.254 0021.1b83.0000,

dst 10.0.61.168 0000.0000.0000 Vlan10

10.0.0.254 is our switch

this started at 10.0.0.0 and is now up to 10.0.65.X

How can I find out what is doing this?

Mike

Re: Switch doing port scanning?

Farrukh Haroon — Wed, 13 Aug 2008 01:42:20 GMT

This seems like a loop on your switch. Disconnect or shutdown all ports, do "clear arp". Verify Spanning tree settings. Is it enabled on all ports? Is there is portfast enabled port?

Which Switch and Version?

Regards

Farrukh

Re: Switch doing port scanning?

burleyman — Wed, 13 Aug 2008 11:48:17 GMT

We found it...it was a misconfigured subnet mask. Thanks for your help.

Mike