Zoom x6 DSL modem & multiple IP addresses (Verizon)

I read a few other postings and figured I should provide more details about the system:

-- At present, the Zoom x6 plays firewall & NAT. A switch is connected to the Zoom's Ethernet port, which goes to the LAN... about 15 PCs, including a server that has various ports directed across the Zoom for, e.g., incoming e-mail, web access, etc. (This is a business class DSL connection -- this is all on the up-and-up.)

-- Why multiple IPs? The company got a new office phone system from Vodavi. It has a VoIP feature, so the 2nd IP is for the phone system's private use (incoming VoIP sessions). Why not just route some ports from a single IP to the phone system? Because -- and this is the answer from the local Vodavi representative -- "Vodavi doesn't document what ports & protocols they use;

---Joel

The Zoom x6 will do static IP routing just fine. From your subsequent posting, you'll have to turn off NAT and the firewall though. So you'll probably be adding another router behind this one. The Zoom won't do concurrent NAT and static routing. Very few routers do.

Thanks for the response, Doug. So I turn off the NAT & firewall options in the X6 and -- poof -- it then just bridges the 5 static IPs over to the Ethernet ports, eh? I'm thinking I'll then connect a Netgear FVS318 to do the NAT/firewall and I guess just plug the phone system's VoIP port into the X6 directly.

I did notice the X6 has a "half bridge" mode where it routes everything to... a single MAC address, apparently? That doesn't sound like it would help here.

If one is assigned multiple IP addresses and you leave NAT on, what happens? It just picks up the first one of the block, perhaps?

---Joel

"bridges" is a very misleading word here. I buy my business services from a local ISP who offers the choice of routed or bridged. If I went with Bellsouth it would be routed only. And routed gives you the 5 IPs. With bridged you'd likely get a login for PPPoE which would assign YOUR router an IP and route all 8 IPs of the block to your router.

Do you have control over the router?

For years I did the Static External IPs and 1 to many NAT and 1 to 1 NAT with Netopia 9100s. They are a wee bit long in the tooth now. I'm looking at Linksys RMxxxx units to replace them. (I want dual WAN support). But you'll not find support for the 3 things at once and multiple static IPs in the $50 after a rebate router.

If you have control over the router see if you can do all of the above. Or at least Static IPs and many to 1 NAT at the same time. If not, you'll need a router that you provide.

I'm definitely not 100% clear on the advantages and disadvantages of routed vs. bridged here!

Right now the Zoom x6 does routing and, yes, I have full control over it. From what people are saying, it'll need to be switched to just to static routing and then I'll use a Netgear FVS318 or similar to perfrom the NAT/firewall.

This is for a small business, so while they are price sensitive, they can afford decent stuff. Actually, pretty much everything seems cheap these days compared to, say, even something as simple as what an old Telebit Trailblazer modem used to cost!

Thanks for the help,

---Joel

If routed and you then need to put your own router behind the ISP's it gets hard to use the block of IP addresses depending on what you want to do. Every router slices out 1 IP address and if you want/need to subnet it gets harder. With bridged you have 5 external IPs for YOUR things. With routed, if you put your own router after the ISP's, you wind up with 4 or less. Depending. :)

Read the Netgear forums before you buy any of their business routers. Some seem to be real turkeys. And this is from someone who's bought a lot of their consumer stuff. And who almost bought one of their dual WAN units before reading their forums. At least they let issues be posted and don't censor.

You should be able to get a non-consumer grade unit for $150 to $300.

If you get one that can route static IPs, 1 to 1 NAT, and 1 to many NAT you'll be set for a long time.

Hi Joel,

Ignoring your specific environment for the moment, a BRIDGE operates at Layer 2 of the Protocol Stack, while a ROUTER operates at Layer 3. Basically, operation at Layer 2 requires less processing (because there are less decisions required) so it is usually faster and simpler than handlng the traffic at Layer 3, however with Layer 3 you get "added functionality" that the Router can become involved with (such as Routing, NAT and Firewall), however the extra processing required usually adds to the transit time of data through the Router. Be aware that I am talking about milliseconds difference here, so the delays are not great.

Also be aware that if a Router only has 2 interfaces (say an ADSL WAN link and an Ethernet port), then static routing is probably all it will ever need, unless you are using some higher layer features of the device (such as NAT and trunking of VLANS to different Ethernet segments).

Cheers.............pk.

Thanks for the clarification, Peter. I believe I've only ever dealt with the routers designed for cable modems & DSL modems that (on the ones I used) were only being used to route one public IP either to many private IPs via NAT and/or specific ports of the one IP to specific ports of a private IP.

As far as I can tell, that Zoom x6 doesn't support a combination of "route one public IP to many via NAT while simultaneously taking the other IPs you have and just bridge them." As such, I'm tempted to just use the DSL modem Verizon provides since I won't be able to make use of the x6's fancier features (NAT, firewall, WiFi) anyway... I want to believe their modem should be the most reliable choice (I've seen the x6 lose the DSL connection and require power cycling once so far in a week, although I realize it could have possibly been the Verizon side of the link that went haywire and not the Zoom).

---Joel

Hi Joel,

This is really all a combination of - 1. What you want to do, 2. What your ISP provides and how they provide it, 3. What your Router is capable of doing. For example, here in NZ, ADSL is provided it 2 main forms, as - A. A "Home" service with only ONE public IP address, B. As a Business Class service where Multiple IP's are provided.

In fact for NZ, the later situation (B.) is quite rare, as a single IP is capable of delivering quite a lot of functionality and there is no real gain in having multiple public IP addresses when one considers the cost of Firewalling them all. Once you get out of the ADSL Networkng world into more real Life Business requirements then things can change, but generally most people in NZ consider 1 Public IP is plenty for a "consumer grade" ADSL service.

One often overlooked features of NAT is its capability to provide basic Firewalling, as its default mode of operation effectively "Hides" anything on the "inside" (or Private Network side) from the "outside" (or Public Network side), but still allows traffic to flow from inside to out quite freely. I am actually curious why you need so many public addresses, is this for a commercial installation?

Cheers..................pk.

Hi Peter,

I agree. If you read my first post, you'll detect a note of disappointment in that the reason they need multiple IP addresses is that the manufacturer of their phone system, Vodavi, doesn't divulge the ports used by their proprietary VoIP card and the company's local representatives will therefore only install the option when they have an entire IP all to themselves. :-( Pretty poor, IMHO (but getting that phone system was not a decision I was involved in). Here in the U.S. small key systems and PBXes are quite often poorly documented -- often purposely so, to "protect" the ongoing sales of the company reps. (Indeed, with this particular phone system, the included documentation doesn't even include how to change the system ime! -- Although the company rep will certainly tell you for asking, but you get the point.)

It's for a small (~10 person) business, and two IPs are being used: One for the phone system, one for everything else. The local DSL provider -- Verizon -- hands you 5 with their lowest level "business" package, so the extra 3 will just go unused for the moment.

---Joel