How to configure router board for common NAT routing?

RouterOS Beginner Basics
1

Hello,

I’m new to Mikrotik. I use a ready to work router board RB75 appliance, see:
http://www.mikrotik-shop.de/Komplettsysteme/MikroTik-RB751G-2HnD::654.html

This appliance has worked very well for me until now. I run it behind a cable modem with normal Ethernet and DHCP (my cable provider runs the DHCP service). Because I was new to MikroTik I have used WebFig for configuration. I configuered the “ether2-master-local” port as my gateway port. I remember it was a simple setup. I did it with little thought. I then connected the “ether2-master-local” port directly to my cable modem (with a common twisted pair ethernet cable). It was working excellent from the very first day.

Unfortunately I had to reset the router board meanwhile (it get unresponsive because of playing around with WebFIG). The reset was successful but after reset I do not get the router board up and running as before. I know that the configuration was pretty easy. But unfortunately I did not document what I had done. :frowning:

Now I did this via Webfig:

  1. I go to “IP → DHCP Client” and start the DHCP Client for the “ether2-master-local” port.
  2. I go to “IP → Firewall → NAT” and add a masquerade rule for the “ether2-master-local” port as outgoing interface.

The “ether2-master-local” port (connected to my cable modem) receives via DHCP a public IP address from my ISP. But than the router board does not begin to route. :frowning:

In my local network the router board has the IP 192.168.88.1.
The gateway of my ISP has the address 84.118.186.1.
If I do a ping to 84.118.186.1 from my local PC (which is connected to the router board port “ether3-slave-local”) I get:

PING 84.118.186.1 (84.118.186.1) 56(84) bytes of data.
From 192.168.88.1: icmp_seq=2 Redirect Host(New nexthop: 84.118.186.1)
From 192.168.88.1 icmp_seq=2 Redirect HostFrom 192.168.88.251 icmp_seq=3 Destination Host Unreachable

(The IP 192.168.88.251 is the local IP of my PC.)

So instaed of routing me to 84.118.186.1 the mikrotik router board sends me an icmp redirect. This is of course not what I want. How can I set the “ether2-master-local” port to router mode? Operates anyone a router board behind a common cable modem over normal Ethernet and DHCP? (without PoE and such things). How did you set it up? Any help is welcome. If you need more information, please let me know.

2

My first wild guess is that your ether2 is master-port to ether3/4/5.
Why not connect ether1 to the modem, which is the gateway port by default.
If you need more help, please post your export compact output from terminal.

3

Yes, this is true.

I did it and it’s working now. Thank you!
Thus, it was because ether2 is the master-port to ether3/4/5? What does master port mean in this context? But I will take a look at the documentation. Thank you so far!