Spoofing on a ISDN T1 Router

[William Wentworth]

                   On one of our Cisco 2921 Routers we have a Serial Interface with a PRI T1 from a Telco that is showing the following:

     Serial0/1/1:23 is up, line protocol is up (spoofing)

                    This does not seem like a issue, but I would like to know if anyone has seen this before and if it should be active on the interface 24/7. We were told that this would be on that interface at all times. To my understanding, Spoofing is a layer 2 problem and not a 'ok thing'. Please help.

[acampbell · Accepted solution]

William,

Spoofing on the ISDN T1 just indicates that the interface has presented itself the IOS and is operational.

Worry when you dont see spoofing.

Regards,
Alex.
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[William Wentworth]

Makes sense now. Thank you.