Blocken von Brute-Force Logins
Block brute force login attempts while maintaining access for legitimate source addresses. This is in theory unnecessary if VTY ACLs are in place, yet things happen and this adds the "belt" to the VTY ACL "suspenders." Note carefully the use of ACL 100 in the login quiet-mode statement. This ensures our legitimate administrator addresses can still reach the router even after a vigorous bruteforce or attack attempt.