#!/usr/bin/env perl

my $line = 'brown vihl729 172.31.176.71:8532503_6 (v2013.02) (elicserv1.muc.ifin.com/3120 6260), start Mon 3/11 18:31';

$line =~ m/(\w+)\s
         ([0-9a-z]+)\s
         [0-9.:()_]+\s
         \(.+\)\s
         \(([a-z0-9.]+).+\)
         ,\s
         [\w\s]+
         (\d+\/\d+\s\d+:\d+)
        /x;

print qq($1 $2 $3 $4\n);

__END__

Karls-Mac-mini:monks karl$ ./missing.pl 
brown vihl729 elicserv1.muc.ifin.com 3/11 18:31