Internal routing problem - ICMP redirect not working

RouterOS General
1

Hi all

As part of testing process before purchase, Mikrotik OS v4.15 was installed on server with 2 network interfaces, one of them was connected to Internet, other on LAN configured with static C class IP address. We wanted to test static routing.

I added 4 static routes to 4 different C class private networks over Cisco router on same subnet as Mikrotik (VPN links to remote locations) and expected that Mikrotik will send ICMP redirects to PC-s who had it as default gateway, but that didn’t happen. No traffic was going to remote locations from PCs.

After that I enabled DHCP server on Mikrotik and it started to work properly - sending ICMP redirects for routes it had entered, PC’s could connect to remote networks via Cisco router. Routing was working as it should.

In the end I disabled DHCP server on Mikrotik and it continued to send ICMP redirects.

Weird. Why did I have to enable DHCP server for Mikrotik to start sending ICMP redirects of his static routes? Not documented, searched trough web/forum/wiki … nothing relevant. I almost gave up on Mikrotik, colleague told me he had same problem and that he solved it this way.

Thanks, regards
Ivica

2

That doesn’t make sense. Can you re-create the issue after a router reboot? Have you talked to support, and sent them debug files?

3

I agree with you, not much sense here. I didnt talk to support because we didnt buy Mikrotik yet, we are evaluating it before purchase so I cant get official support in this case (correct?), but I assure you that RouterOS is behaving exactly this way because my colleague had same situation with his device and he told me how to make it work.

Recreating issue should be easy - take RouterOS, install in on machine with 2 NICs, configure one interface with static IP, add static routes and thats it. I cant do it at the moment because my machine is working properly once I enabled DHCP, but I am sure Mikrotik support could test this, it should be in their interest to find a bug in OS, if it really is a bug.

I will probbably test it when i have time, no way I’m gonna buy a router before this issue is resolved.