One VLAN experiencing delay in reaching internet

[Shobith K]

We have a 4500 chassis with 4 VLANS, from last week we have found that from one VLAN users are facing latency in accessing internet and some times they loose packets. I can see a lot of request timed outs, some times i have even faced - some users are able to ping to internet but not to the router --strange ...

I have put the same port in some other VLAN and is working fine. I doubt some virus activity.

How can i determine any abnormalities in the port by using any commands, suppose any abnormal actvities like broadcasts or any other factors...

[sachinraja]

hello shobithk,

In case you have a syslog server , it will record all such activities in the switch/VLAN.. also, see if the broadcast counters on the "show int vlan" command is increasing or not.. you can eliminate the PCs puming huge traffic and then check..

all the best...

[Kevin Dorrell]

Another thing to look out for is if some bright user has configured a PC with the same IP address as the default gateway for that VLAN. When a user is having problems, look at his ARP cache entry for the router, and make sure the MAC address corresponds with the real router.

Kevin Dorrell

Luxembourg