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New Member

Cat 3550

We use a Cat 3550

as the Gbit backbone of our network

When doing analysis of from the NIC ofmy PC it seems to be sending out alot of broadcast(arp) 45-50% of traffic

It is not configed to run as the DHCP server.

Can anyone tell me if it should be broadcasting?


Re: Cat 3550

What is it arping for? Is it sequential IP addresses constantly? If it is I would suspect a Virus or over-active Management Software. It could also be bad configuration - i.e. your PC is configured to access certain machines that don't exist??


New Member

Re: Cat 3550

Not sure why its arping? (why it is my question)

it is seq broadcasting!

ie. ARP protocol who has 4.5.x.100 (using ethereal)

ARP protocol who has 4.5.x.101

how could it be a bad config?



Re: Cat 3550

If the arp requests are constantly going up:

i.e. who has 4.5.x.100

who has 4.5.x.102

who has 4.5.x.103


who has 4.5.x.254

Then I would suggest either a Virus or Management software trying to scan for new devices (more likely to be a virus as you would know you are running management software?).

Bad config - I mean your PC is somehow configure to access some IP devices (for whatever reason I don't know) and it is trying to contact them. Your PC will have to ARP for anything on its local subnet that it needs to communicate with before it can establish a connection as it must resolve their MAC addresses.


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