Doesn't this do what you want?

#! perl -slw
use strict;

while ( <DATA> )
{
    chomp;

    if ( $_ !~ m[/user/prot/$] )
    {
        print qq{Disallow!! [$_]};
    }
    else
    {
        print qq{Allowed. [$_]};
    }
}

__DATA__
/user/prot/
/user/protrusions/
/user/a/
/user/backups
[download]

Output

P:\test>test2
Allowed. [/user/prot/]
Disallow!! [/user/protrusions/]
Disallow!! [/user/a/]
Disallow!! [/user/backups]
[download]