Does the phrase "interesting traffic" only apply to traffic between two IPsec peers or does it apply in other situations as well?
Keith, I think that could be a form of crosstalk. At least the tx and the rx are interfering with one another.
Personally, I find ALL of my traffic to be interesting.
They should create something called "irritating traffic", that would be more fun to define.
Anyway, anything using a dialer interface (which includes legacy things like ISDN/modems but also includes newer things like PPPoE) or crypto maps will use ACLs to define interesting traffic.
Technically anything calling an ACL or something to match traffic is looking for things that are locally "interesting" but we don't typically see that phrase used other than the instances above.
I think that "irritating traffic" sounds much more appropriate. Otherwise, I picture catfish and eagles.