Hi everyone,
I have a Cisco 871 router. It has been in a box for a few years, but the other day I pulled it out in an effort to try to relearn how to use it.
Anyway, I have it all set up - I have it connected to a DSL modem, and behind it sits my ASA5505. The 871 is just a border router - its there to pass traffic and do ingress/egress filters.
My question involves SPAN ports. I understand how to set them up. My problem lies with trying to monitor my WAN interface - i.e. FastEthernet4. Whatever I try, the cli refuses to accept FastEthernet4 as a source for SPAN.
I am using IOS 12.4(11)T2.....I have also tried 12.4(24)T5....but I get the same issue. I have no problems setting VLAN1 as a source for SPAN....or FastEthernet0 thru 3.
For some reason, when I used this router a few years ago, I recall having this problem....but IIRC I was able to work around it...but maybe I am remembering incorrectly.
I have searched high and low both on Cisco.com and elsewhere on the net, and have not found anything that indicates the 871 is unable to use FastEthernet4 or its WAN interface as a SPAN source. Heck, my ASA5505 can use its WAN port as a SPAN source.
So am I doing something wrong? Or is this router just unable to do what I am asking it to do?
Thanks,
Mike
PS I know I can put a hub or a passiver ethernet tap between the DSL modem and the 871 and accomplish the same thing...but thats not the point. If it is possible to do monitor the WAN interface via SPAN, I would like to be able to do this.
Thanks,
Mike
