Also, from your original regex:
/.*Interface-Down\sIF-*.*.*.*./
#1: There is no need for the leading .* since you don't have a ^
#2: the *.*.*.*. is not probably not what you want to do? Unless you mean 0 or more - ? Should probably be .*.*.*.* but that doesn't make any sense either, unless you do .*\..*\..*\..*
#3: That random / in the middle is just gonna break stuff unless you escape it. The way it is now, it's gonna stop your expression there.
#4: Repeat..
May I also recommend a regex cheat sheet? Something like this.