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Broadcast Problems

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thebdj

Technical User
Oct 21, 2003
27
GB
On interface FastEthernet0/0 on my Cisco 2621 router, there is a ridiculous amount of broadcast packets.

What measures can I take to try and reduce this, as I believe this is causing serious bandwidth problems for this network.

Appreciate your ideas
The BDJ
 
Your router is broadcasting or it's getting a lot of broadcasts?

"I can picture a world without war. A world without hate. A world without fear. And I can picture us attacking that world, because they'd never expect it."
- Jack Handey, Deep Thoughts
 
"Received xxx gazillion broadcasts" :)

Cheers
 
You need to put a sniffer on the local segment that's getting all these broadcasts and find out which machine is causing you your problems. You might have a NIC card going bad causing broadcast storms.

You can download free sniffer software from the net, although I don't have any suggestions on which ones to use.

Some devices like a FLUKE One-Touch can identify PC's that are broadcasting a lot as well. But these types of devices can be expensive. Good luck finding your machine.

"I can picture a world without war. A world without hate. A world without fear. And I can picture us attacking that world, because they'd never expect it."
- Jack Handey, Deep Thoughts
 
IPKONFIG has the right idea. You need to specify WHAT broadcasts are burying the router. Some are needed, some are not and some are a warning that you might have a virus/worm attack under way such as Nachi. Other causes of broadcast storms can be a misconfigured network. The sniffer is probably the easiest and quickest way to find out just what is on the wire.

We have links to several free Linux and Windows based sniffers at If you Windows, take a look at Packetyzer which is a very nice GUI frontend on Ethereal.

MikeS


Find me at
"Take advantage of the enemy's unreadiness, make your way by unexpected routes, and attack unguarded spots."
Sun Tzu
 
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