Routing for Verizon FIOS -- Reward for answer

Can you get verizon to sell you another separate /31 (yes a /31 works, we use them all the time for point to point routing adjacencies) and then setup routing on both sides? Else I don't see why you can't carve out the /30 as you have said, and ensure that Verizon and you are advertising properly on both sides. Or install a switch between them and you for external hosts and NAT for anything going internal. Not sure you can do that with FIOS, never had to deal with it.

It is never "best" to simply route traffic to your inside network. The only reason you need a public IP is if you are accepting connections from an internet source, which should only be a few devices (your mail server, web server and VPN concentrator, etc.) All of your inside traffic for web browsing can be NATed to a singe outside address Your video conference station should be able to have two addresses, the inside address on your LAN, and the outside address that it is NATed to.

You can also request a separate address from Verizon so that the connection between your router and their connection is on a different subnet than the block they assigned you. If you can't do that, your only option is to bridge the traffic which, in my opinion, is the worst case option.

Out of interest, could you not assign the ip address to the LAN side of the router and on the WAN port use ip unnumbered to the LAN interface.

int Fa0/X ip address 70.x.x.X /26 int Serial X/X ip unnumbered Fa0/X

I seem to recall I have have done this in the past mainly on ADSL boxes where the client wanted to present a public IP address internally..

Regards

Darren

1. It appears that the router in question is using a Fast Ethernet interface facing the FIOS ONT. If this is in fact the case then an ip unnumbered command will be rejected on a multi-access interface. ip unnumbered can only be used on point-to-point serial interfaces.

1. The following static routing construct is viable: ip classless ip route 0.0.0.0 0.0.0.0 70.x.x.1 ip route 70.x.x.1 255.255.255.255 FastEthernet0/1

Option D would probably work but it is definitely a cludge.

The suggestion by other responders to approach Verizon to see if they will provide a /30 or /31 for the FIOS link would definitely be worthwhile pursuing.

However be forewarned that if Verizon has not planned for this "feature", it will impact their service provisioning systems and they will less inclined to provide what you are looking for - i.e a /30 for the FIOS link.

I hope that's true -- it would seem to be our only serious alternative to double NATing. I agree it's unusual -- do you know whether there's some specific downside, from the standpoint of performance or reliability? Do you think we will need arp proxy to make this work (which our current config does)?

if you configured say 70.x.x.2 on the "inside" FE router interface and made that the default gateway for all the devices, then proxy ARP could be disabled on the inside interface

Proxy ARP would need to be enabled on the outside interface to answer ARP request for 70.x.x.y coming from the Verizon router @ 70.x.x.1

You could try the following to see if it works for you from both a connectivity and a performance perspective, save your current config before doing so.

int fa 0/0 description inside LAN interface ip addr 70.x.x.2 255.255.255.192 ! default gateway for devices on LAN

int fa 0/1 description outside interface facing Verizon FIOS ONT ip addr ip proxy-arp ! in order to be able to answer ARP requests from

70.x.x.1

ip classless ip route 0.0.0.0 0.0.0.0 70.x.x.1 ip route 70.x.x.1 255.255.255.255 FastEthernet0/1

I think the issue is that his range is ..64/26, and he was told to use .66 as his router w/ a 24 bit mask (so he can hit .1) and not to use anything else. Therefore I'm not sure he can put a different address on that external interface, and there is no easy way to subnet without cutting out half of his assigned addresses. If he uses the first set to assign a /30, then he can't get to Verizon's router, and if he could, then he can't easily subnet whats left without vlan'ing it into a /30, a /29, a /28, and a /27. What a pain, I'd be screaming at verizon for a /30, even if its not public.

I wonder if he could ask Verizon to put a secondary IP on the VLAN of interface on their router, say .67. Assign a /31 point to point for the router uplink, then have the router split up the /30, /29, /28, /

27 (presuming his switch is not a L3 switch), and trunk it to the switch. He will lose some addressing for network/broadcast addresses, but this could work. He would then be effectively giving Verizon one of his own addresses. Would that work?

Oh I would definitely pick up the phone and call again ...

I wonder if this would work:

int fa 0/0 description inside LAN interface ip addr 70.x.x.66 255.255.255.192 ! default gateway

int fa 0/1 description outside interface facing Verizon FIOS ONT ip addr ip proxy-arp ! to answer ARP requests from 70.x.x.1

ip classless ip route 0.0.0.0 0.0.0.0 70.x.x.1 ip route 70.x.x.1 255.255.255.255 FastEthernet0/1

Merv,

That's exactly what we're planning on trying next.

As to calling Verizon: our problem is that FIOS was originally designed as a consumer service, and the support & sales staff reflects that. There is no such thing as specifying how a line is to be provisioned, or even asking a support person how their network behaves. There is only three options when you order a FIOS line: speed, static IP, and multiple IPs. You can only get one block. That's what's programmed into the sales staff's system, and they have no way of putting anything else into the computer.

When you ask tech questions, everyone says "well it works if you use the Actiontec router we gave you." If you say "but we have a Cisco", they tell you that they would be beyond their "legal boundaries" to discuss how it might be programmed.

Why are we putting up with this? We are getting 30 MBit down, 15 MBit up (and we do get that) and 61 IPs for $359.99/mo (vs our T1 which costs about $750/mo.) We're the serious real Business FIOS location in our city, and we're willing to do a bit of bleeding-edge work in order to get the bandwidth.

For that kind of speed I would be willing to figure out how to make water flow uphill ...

If Verizon is willing to put a secondary IP on their router/vlan interface, I think you may have a not-so-ugly solution. If not, not sure what else to tell you.

| OPTION D: We could assign a PRIVATE address to the outside of our router -- | say, 10.1.1.1. But then, how would we direct traffic to our gateway? If we | provide a default route just by interface | | ip route 0.0.0.0 0.0.0.0 FastEthernet0/1 | | then it's got to ARP for every single outbound address. QUESTION: would the | following solve that problem: | | ip route 0.0.0.0 0.0.0.0 70.x.x.1 | | ip route 70.x.x.1 255.255.255.255 FastEthernet0/1

Although it isn't often seen, you can specify the next hop directly on a route to an interface:

ip route 0.0.0.0 0.0.0.0 FastEthernet0/1 70.x.x.1

That's the approach I'd take, with proxy ARP enabled on the interface to handle incoming traffic and an arbitrary address as you suggest in option D. Depending on how you set up the inside routing you might accidentally respond to ARPs for a few extra addresses, but then Verizon shouldn't be ARPing for those addresses in the first place.

Dan Lanciani ddl@danlan.*com

1 suggestion is rig up Wireshark to look at what is actually happening on the outside interface.

some real info is worth a lot of guessing.

you can NAT an address to be the same address after it is translated (or at least you can on a PIX) - any use?

use up a small amount of addrssing from your block for a /30 to have a link to the FIOS next hop.

So your outside would be

70.x.x.2 255.255.255.252

then you have an inside subnet for the full block, and let proxy ARP fix up the next hop stuff for FIOS.

Cost is you lose some addresses for the reserved part of the /30 (and the complexity and debugging of course).

this depends on the 1800 allowing you to set up overlapping subnets - used to work a few years back, but i havent tried recently........

I believe that Trendkill has already pointed out the negative impact of attempting this approach:

"then he can't easily subnet whats left without vlan'ing it into a /

30, a /29, a /28, and a /27"

Yes, he can't use .2. He has been given .66 - .126, and .2 is off limits. If he takes .68/30 (he was told to avoid .65 for some reason as well), then he has to vlan/subnet the remaining portion of the /26 into a /28 and /27. Not all that bad, but just a pain to have to deal with and he loses several addresses. The problem here is Verizon has not come to the table and said they will do anything, and if he uses .

68/30, he can't get to their .1 interface anymore (they want him to use the full /24 and only use .65 - .126.

This is why I was saying that if Verizon's FIOS router has a /24 and a IP of .1, why can't they turn up a secondary virtual interface on it (secondary IP) of .65 or .69? Then he can do the above to use a /30 and vlan/trunk the rest which is a pain but will work. If Verizon is not willing to do that, then he will have to attempt one of the above solutions with default gateway-next hop interface, etc.

Although on second thought, this would work on the way out, but not the way back in, as the Verizon router still thinks its a .24 and would most likely not route to the next hop to get to the .64/26 network. The only way to make this clean is to get them to assign a /

31 or /30 that is not in the /26 they have assigned you or the bigger / 24 that holds it that they insist on forcing upon you. Even if it was a private IP'ed point to point, that would be fine, provided their routing is correct, but I'll bet they don't want to split up that /

1. Have you asked them if there is another block that they can assign you that will allow the usage of a /30 or /31 for this point to point purpose?

What is bit strange here is that of having a service were Verizon dishes out a /26 which is beyond anything a normal residence would require unless it is a multi-unit dwelling. This really is a an business Internet service offering but it certainly appears that it is not being supported as such.

Unfortunately teh OP does not have access to a Verizon SE or account manager. If I were him I would write to the President of Verizon and request to be directed to someone in the Verizon organization who can address this business issue.

It is really a pretty wild situation. There appears to be not a single person in the FIOS business office or tech staff who knows ANYTHING. They can only read scripts and fill in forms which have been provided to them. I will definitely be trying to find some less-formal way way into the organization, or looking to see if there's anyone else who has dealt with this problem.

Based on numerous tests, I have come to the conclusion that the router/switch on Verizon's side is totally spoof protected: It will not respond to an ARP query unless the source address is one of the 61 addresses assigned to us (we've tried .2 and also tried assigning 10.1.1.1 to the outside of the router, and giving a static route to our gateway.) In one case, .2 worked briefly -- probably because we had just swiched over, and it had an association of our MAC address with a valid IP. In that configuration, we could route in/out of our network, but couldn't ping from the router to the gateway. Once that timed out, we were blocked, again.

We have one remaining option ("OPTION B", in my original post) which is where I think we will end up for the medium term: We will route & NAT

70.x.x.66-.126 on the outside to 10.0.0.66-.126 on the inside. Then, we will NAT again in our ISA server to our LAN and Service Zone addresses. Our VideoTeleconference units, outside the ISA server, can be told that their inside a NAT which is not H.323-aware, and they will work just fine.

While we may need to make additional adjustments to a couple of other devices, there is ONE upside advantage to this: once we've got it working, none of the inside hosts will need to be aware of their public IP addresses. It also means that if the router falls back to the T1 line, or we switch ISPs, this will be almost totally transparent to everybody (the VTCs will need to have us adjust "IP Address to Show in Global Phone Book.")