Hi Gurus,
I just had something very strange happening on my Mikrotik 4011 Router and I hope someone can give me context.
To explain what happened and confused me, I’ll just mention the configuration of the relevant parts. I had WAN access (dhcp) through eth1, Ports 2-4 and 6-9 are part of the same bridge (dhcp, network 10.2.0.0/23), Port 5 is “isolated” by way of not being part of the bridge, having its own static IP address (192.168.1.5), network and DHCP server set on my router.
I changed my internet provider, have now access to fiber. So I disabled the dhcp client on eth1, installed the sfp module for fiber (sfp1) and connected the fiber cable, set a dhcp client on sfp1 and made it part of the WAN list, removing eth1 from the same list. All done, all works, I have internet.
I then received messages from the people behind port 5 that they can no longer access the internet. This surprised me, after all, I didn’t make any changes whatsoever to other ports except eth1 and sfp1, and these are not bridged in any way with other ports. And since my firewall rules use lists, the change from eth1 to sfp1 shouldn’t make a difference (and it should affect me, too).
To my big surprise, this is what I encountered in the IP addresses section: The IP address I originally assigned to eth5 (192.168.5.1) was now assigned to eth1. Trust me, I did not make this change, this was done by the system itself.
Clearly, the issue is solved now, it was just a matter of changing eth1 to eth5 in the IP address association table. Still, I’d like to better understand what happened here. Is this some sort of bug in RouterOS, did I maybe do something in a way that’s not considered correct?
Thanks for your input.
Vic
