> ip extcommunity-list 100 permit 3549:4[0-9]*
> ip extcommunity-list 100 permit 3549:4.*
Unless you are trying to match extended community attribute, I don't
think you should be using "extcommunity-list", but "community-list".
The following should do the trick:
ip community-list 100 permit 3549:4[0-9]*
Marko.