Initial setup of NAT and Default Route

RouterOS Beginner Basics
1

I’m just getting familiar with the RB750, so please excuse my ignorance on this.

Looking at the initial configuration pages at http://routerboard.com/pdf/356/rb750gl-ug.pdf , I believe it appears the default Firewall/NAT settings should work (what I see matches what’s shown on the page).

The next thing is the default route. The manual page gives no information as to what the meaning of all the various fields is or how they should be set. The only field described is the gateway, and it says that’s something provided by the ISP. My ISP has not provided a gateway IP. Just a static IP and some DNS addresses. Other routers I’ve used (Linksys, Trendnet) do not ask for an ISP gateway. So… what do I need to do here?

A couple other notes on the configuration:

  1. I set up a PPPoE client on Ether 1. It appears to be connecting to the ISP.
  2. I set the DHCP range to 192.168.1.100 to 192.168.1.254. It appears to be giving out IP addresses correctly.
  3. In IP/DHCP, I put in the ISP provided DNS addresses. They seem to be sent properly to DHCP clients.

The big problem right now seems to be the default route to get NAT running. After that, I’ll start dealing with port forwarding to handle servers.

Any help is greatly appreciated!

Harold

2

On your PPPoE client check the Add Default Route box, then it will add it automatically.

Then if you are using NAT make sure you have a masquerade rule in the src-nat chain, with out-interface of your PPPoE client.

Hope that helps

Nick.

3

Thanks! I’ll check that out next weekend (when I have some free time!).

Harold

4

I finally gave this a try and am still having trouble. Here’s what I tried:

IP/Firewall/NAT - Add New.

chain: srcnat

out inteface: pppoe-out1

action: masquerade

Everything else left blank.

Hitting Apply causes “invalid” to appear below the OK button.

I also tried in-inteface of ether-2-master-local, but that did not help.


So… any more ideas? Is more step-by-step documentation available?

Thanks!

Harold

5

OK, I’ve made some progress! Here are my notes. I’m next going to work on port forwarding. So, after starting with the default configuration and doing the following, I was able to reach the outside world! This appears to be a powerful router that presents us with LOTS of options. The trick is figuring them out. So… here’s what I’ve done:


Reset router to default settings by using a paperclip to hold down restore button during powerup. Hold button until LED starts flashing.

Default IP address is 192.168.88.1 .

Use webfig with username of admin and blank password.

ip/addresses – Set LAN address to 192.168.1.1 .

Change laptop to something in this address range to reconnect (ie, 192.168.1.250).

ip/pool – Set DHCP address pool.


Interfaces/Add New/PPoE Client – Username xxxx Password xxxx
Interfaces ether1-gateway.

ip/firewall/nat – Set up NAT. Set properly by default, but change out interface to pppoe-out1. This must be set with PPOE active (connected) or it will show as invalid.


ip/dhcp server – remove existing DHCP, then – dhcp setup
Server Interface – Ether 2 master local
DHCP address space – 192.168.1.0/24
DHCP gateway – 192.168.1.1
DHCP addresses to give out – 192.168.1.100 – 192.168.1.254
DNS servers - xxx xxxx xxxx
Lease time – 3d 00:00:00
Hitting next after lease time is set establishes DHCP server, though screen does not show any change.

6

Thank you very much. This has helped me get through the initial PPPoE configuration I have been searching for endlessly. :slight_smile: