Hello.
I am working with Cisco 1600 and Mikrotik RouterOS at the same time.
I need to configure the Mikrotik ethernet interface as "no ip redirect" it means the interface does not send ICMP messages to the network conected. These ICMP messages change hosts gateway on the network by redirecting the packets to another gateway. You can see it on the route table on some host. (Windows Command: route print ).

I could configure that on Cisco but mikrotik!


HOST IP ..10.5 and GW ..10.1
|
|
|---------..10.2 CISCO ------------>Cis ROUTE.
|
|
----------..10.1 ROS ------------->Mik ROUTE.
.
I am ussing mikrotik as main gateway and Cisco as Backup route.
Mikrotik Has got 0.0.0.0 --> ..10.2 as gateway of last resort.
When Mikrotik Route falls down, it redirects all packets to ..10.2 but the host inmediately changes its gateway to ..10.2 because Mikrotik Interface sends that "ICMP message"! then, if the mikrotik route comes back available, the packets are still going through Cisco gateway because the host has changed its gateway!
All this become normal when have passed 3 or 4 minutes because the new gateway on the host has timed out.

Using Cisco (rather than mikrotik) and the commnad "no ip redirect" it does not happend.

COuld somebody help me? I AM VERY SORRY BECAUSE MY ENGLISH.

Thank you a lot! Ivan Perino-
ARGENTINA

You can simply block ICMP 5:x codes on the output chain. You should always block these on the input chain so mIkrotik ignores them as well.

http://www.iana.org/assignments/icmp-parameters

Sam