How to use a subnet'd public IP on two interfaces

RouterOS General
1

I am trying to subnet a class c of public IP's that I have and let one of my users have a /29 on the lan side of the RouterOS.

Here is a layout of what I have

Edge Router x.x.x.1/30
|
|
x.x.x.2/30
___|Wan
|_RouterOS Box|
|E1 | E2
private Network |
|

| |
2nd Private Network RouterOS with x.x.x.161/29 on one interface
|
|

| | | | |
x.x.x.162/29 x.x.x.163/29 x.x.x.164/29 x.x.x.164/29 x.x.x.165/29

I can route between the any of the client equipment with the /29 and both private networks and x.x.x.2
but any attempt to get to x.x.x.1 or further is not working....

I made a post before but didn't get any responses maybe because I didn't explain it well enough. I think lays it out pretty plain.

If someone has an idea why the /29 is not routing to the .1 please give me an idea to try

I have my default gateway set to the x.x.x.1

Also I do NOT want to NAT the /29 I would just like to route it to the x.x.x.1

Thanks

2

I have my default gateway set to the x.x.x.1

Your default gateway for that subnet is .161, not .1. Everything else looks right.

Sam

3

The default gateway on the RouterOS box is x.x.x.1 the default gateway on the equipment is set to x.x.x.161

That still is not the problem…it almost seems as if it will not route a subnetted class C??

Any ideas on how to get this working?

Thanks in advance

4

the edge router has a route x.x.x.0/24 to the RouterOS Box?

5

Show us the routing tables in your two ROS boxes…

6

Dataphd -
Upon reflecting on your post - I was looking at a few others trying to help out… I realized that you may not be routing the way you expect to be…Let me put an example here and see if we can get you going in the right direction…

One of my setups has a T-1. Cisco (example - not real IP address)
WAN side - 216.199.55.2/30
Lan side - 216.199.55.5/30

My WAN MT IP address is 216.199.55.6/30

The upstream router from my T-1 is routing all data destined for IP block 216.199.3.0/24 to 216.199.55.2 (Cisco WAN side)
Cisco is told that 216.199.3.0/24 should be routed to 216.199.55.6 (the WAN side of MT box) which the Cisco happily does…

Now the MT box has 216.199.3.0/24 being routed to it… From here I can do whatever I want - NAT, make my own subnets, whatever.

In your case you now have a private IP range on the LAN of MT1 - so for fun we’ll make it 10.1.1.1/24 as the LAN address on MT1 and 10.1.1.2/24 as the ‘WAN’ address on MT2.

Private LAN side of MT2 is 10.2.2.1/24

Let’s say we want to route 216.199.3.0/29 out and have it present on the LAN side of MT2.

Here we go…

MT1 route 216.199.3.0/29 gw=10.1.1.2 (this points to WAN side of MT2)

MT2, we now add 216.199.3.1/29 to the LAN side of MT2
Default (0.0.0.0/0) route on MT2 = 10.1.1.1
Clients on LAN side of MT2 that need to use 216.199.3.x/29 IPs would have their gateways pointed at 216.199.3.1 the LAN side of MT2

So it looks like this:

Internet<->WAN 216.199.55.2/30 Cisco LAN side 216.199.55.5/30<->WAN 216.199.55.6/30 MT1 LAN 10.1.1.1/24<->WAN 10.1.1.2 MT2 LAN 10.1.2.1/24 AND 216.199.3.1/29<->clients

Ok that’s it…drop a line back and let us know how you did.

R/

7

is your provider routing or bridging the traffic to you ? Maybe they aren’t routing it and are simply putting the whole /24 on the wire (arping).

Sam