Remove characters from logging Irule entry

The scan and regsub commands both work on regular expressions, so both will do a better job of matching a dynamic set of numbers - at the expense of performance. I'm doubtful that you have a large set of dynamic route domain assignments, so given the assumption that 1) it's a small set, and 2) you already know what those RD values are, an explicit [string map] is probably more efficient. But I want to express that [string map] is an explicit search - you have to know what you're looking for. In your case, since "223" is the RD number, your syntax would look something like this:

string map {%223 "" %224 "" %225 ""} [IP::client_addr]