cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
525
Views
1
Helpful
1
Replies

CRC errors caused by having 2 IPs?

brianbanks
Level 1
Level 1

So far, my experience with CRC errors are that they are pretty much 100% hardware related.

Usually cables or bad ports, and one time a whole line of switches had a bad chip on the gig port.

A couple of days ago, I troubleshot a workstation that had a terrible connection. Checking the port stats I found that there were a rediculous amount of CRC errors, almost no collisions and tons of dropped packets. This was on a switch that had only a CU connection to a computer and fiber back to the backbone. The CRCs were on the fiber port. I spent forever troubleshooting thinking I had a bad fiber until I discovered the computer had an extra IP configured. One was in the correct subnet, the other was a 192.168.x.x address. Once I deleted it, everything was great.  I checked 24 hours later and the port stats were still perfect.

I'm just hoping someone can explain the *why* of this one. I hate not knowing the reason for something.

1 Accepted Solution

Accepted Solutions

Richard Burts
Hall of Fame
Hall of Fame

Brian

That is a quite strange symptom. I am not sure of the cause and wonder whether it might be that the computer was sending frames for the second IP and doing something like adding a vlan tag - which the switch access port would not expect and would generate CRC.

HTH

Rick

HTH

Rick

View solution in original post

1 Reply 1

Richard Burts
Hall of Fame
Hall of Fame

Brian

That is a quite strange symptom. I am not sure of the cause and wonder whether it might be that the computer was sending frames for the second IP and doing something like adding a vlan tag - which the switch access port would not expect and would generate CRC.

HTH

Rick

HTH

Rick
Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: