Adding 2nd DSL, trouble going through RB1100

RouterOS Beginner Basics
1

[ I posted a similar question to General, had quite a few views, but no replies ]

Not new to networking, but relatively new to Mikrotik…

We have an RB1100.

We have one DSL modem plugged in to a port on a Cisco router. The DSL modem connects via PPP to the DSL provider’s network. They route 216.x.144.66/26 to us. All via static routes, the Cisco breaks up the IP address block in to smaller subnets. Another port on the Cisco is connected to a switch. That port on the Cisco is 216.x.144.113/28 All other subnets from the /26 (a /28, and /30s) are statically routed to the RB1100, which is 216.x.144.116/28 on it’s ether13 interface. Other things are connected to that switch, and other things are connected directly to the RB1100. Everything is working fine.

We are now trying to do some testing with the 2nd DSL connection, directly connected to the RB1100, without taking down what is currently working if possible. The DSL provider is routing 216.x.236.192/28 to that one. I set the RB1100’s ether3 interface, which is plugged in to the DSL modem, to 216.x.236.194/28, I can ping both .193 (modem) and .194 from the outside.

We plugged a host in to ether4. No matter what I’ve tried, static routes, route marks, firewall rules, proxy-arp, … I can’t reach that host from the outside.

What I’m doing is not working. I would appreciate some guidance on what I should be doing to get that host to be reachable from the outside using a subnet smaller than what the DSL provider is providing. That host is set to use 216.x.236.197 as it’s default gateway and it is 216.x.236.198/30

I know I can probably manage NAT for this host, but I’d like to leave the host configured directly to use that “real” IP Address if I can.

Thanks in advance

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The hands down cleanest solution is to ask the ISP for an actually routed block. Currently they aren’t routing you anything: they’re directly connecting some public IPs to you. In a routed solution you would get different IP space than what is on your WAN port routed via your IP address on your WAN port. For example, you could be 1.1.1.2/30 using 1.1.1.1 as your gateway on the ISP side. The ISP then routes you 2.2.2.0/24 via 1.1.1.2, and you can use any IP address on 2.2.2.0/24 behind your router as you see fit.

Investigate that option first, and see if the ISP can arrange that for you. It is much, much cleaner than what you’re trying to do.

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Thanks for the supporting information. Very helpful to be able to show a 2nd opinion.

A bunch of trouble tickets, countless e-mails, and a 4-way conference call later, I think we’ve got them to agree to give us a new /30 for each one and they’re going to route the existing IP blocks there.

Wish me luck (I know what to do, I just hope they do )…

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Good news. Once that is in place this will be a very simple network, which makes it more stable, and easier to troubleshoot. Good luck.