"The logging of errors SHOULD be restricted to conflicting information

"The logging of errors SHOULD be restricted to conflicting information
that causes hosts to switch from one value to another with each
received advertisement." (RFC 4861)

Receiving of RAs on non-advertising interfaces is not a conflicting
information; don't log it.

"Mike." (the.lists AT mgm51 DOT com) reported that this
leads to excessive logging with certain cable providers in 2013.
Recently reported again by Aaron Riekenberg (aaron.riekenberg AT gmail
DOT com). Thanks!

OK bluhm@