#! /usr/bin/perl -w
use strict;

my $test = "10.100.71.67.log:MikroTik v2.9.50";
my ($ip,$model) = split /:/,$test;
$model =~ s/\.log$//;
die if $model =~ /log/;
print "<$ip> <$model>\n";

output

[john@scan log]$ ./test.pl 
<10.100.71.67.log> <MikroTik v2.9.50>

[john@scan log]$ perl -v
This is perl, v5.8.8 built for i386-linux-thread-multi