Home Forums Networks & Cross-Platform Networking Static or Dynamic IP?

When I first got DSL I had no choice and was given a static IP address (I've since been told this is a very good thing). Over the years I have replaced my router, but the ADSL modem is the same (12 years old and still ticking).

With this last router replacement, based on discussion in this forum, I went for a dual band router. After nearly 2 hours on line with the tech, he concluded that the new dual band router requires that I have a dynamic IP address. Is this really a requirement for dual band routers? Or perhaps for some age-related reason the router is not recognizing my ADSL modem?

Any thoughts would be appreciated.

You have a tech that can't figure out whether your hardware is defective or his instructions are wrong, and is unwilling to admit it, and is providing a bandaid solution.

It seems that as a general rule today, phone support won't admit to not being able to find an answer, and will instead look for an answer, any answer, that will alleviate the most obvious part of the problem, and get you off the phone. (they're not in the business of finding a good answer, they're in the business of finding an answer)

I'm fairly certain I would fail at the task of finding any router for sale today that did not support a static WAN address. There may be a misconfiguration in your modem that your previous router accidentally handled as desired, that needs to be corrected.

That being said, not all useless phone support is entirely useless. Many times in the past I've called into my isp or applecare etc and spent time discussing the problem, and simply having a sounding board and a person asking questions and suggesting ideas sometimes stimulates my own thought process enough to consider possibilities I hadn't thought of. So even if they don't provide the solution, they often help me find it myself, and we both learn something new. Or sometimes I finally conclude that I'm just SOL and there's no satisfactory fix available. Now that's not a desirable answer, but it is an answer, and an answer is what I needed.

Your reply is actually somewhat helpful, so thank you. First, it reaffirms that I'm not crazy (at least on this issue) since all my previous set-ups worked. Second, the dialog with the tech support person actually did provide me with some thoughts about how to make it all work, which I will eventually try (after getting over being pissed at ending that session with no working router).

Now, a "misconfiguration in your modem". The tech support did throw out the phrases "half bridge" and full bridge", but not as a solution. Does that add any more to finding a solution to my problem?

And we can say with great certainty, dual band routers should work with static IP addresses??

More thoughts anyone?

Possibly. Many current modems have both modem/router and modem-only functions, and may default to the former, e.g., after resets or power cycling. If your modem is such a dual function critter, make sure it is in 'bridge' (modem-only), NOT router mode to leave the routing to your new router.

To verify the bridge/router setting or to effect a switch, modem setup pages can be accessed in a way similar to those of routers, but as I don't know your modem make & model I can't tell the IP# to use for access. Your ISP should be able to give you the details of the modem. Alternatively, its make/model info may let you find the goods on Google.

I don't usually see modems or routers referred to as a "bridge". I'd speculate they are talking about whether or not the device performs NAT, breaking out one WAN IP address into a subnet of 10. or 192. internally for all your devices. "half bridge" and "full bridge" may describe what is more commonly referred to as "passthrough or NAT".

In the case of passthrough, your computer (or router) is requesting via DHCP an address, and is being provided by your ISP, not your modem. (the request "passes through" the modem to the ISP) In that case the modem is acting as a transparent piece of hardware as though the ethernet cable was run from your router straight to their patch board at their office.

For non passthrough, your modem is performing NAT. Usually it's not recommended to have another router follow that, which is likely to NAT yet again. Stacking NAT causes performance problems and usually makes UPNP dynamic portmapping not work. Airports will turn their light yellow and flag a problem if they detect they are set for NAT, and their uplink is also providing NAT. A switch is usually sufficient in those cases instead of a router. Or you can just turn off NAT on your router, and it becomes passthrough, basically functioning as a switch. A router can be useful though if it's providing your wireless.

So if your modem is set to passthrough, configuring your static WAN address must be done in your router. Otherwise it needs to be done in your modem. (if your modem is passthrough and so is your router, or you use a switch instead, static must be set up in your computer)

In response to the above two postings:

The modem is 12 years old and to my knowledge, was never a router/modem combination. Indeed, without a router, I've never had wireless capability on the network.

On all previous modems I have set the static IP address in the router, with success. It was only with this new dual band router that the problem arose. Perhaps it has a new "sensitivity" (as previously suggested) that is coming up with the older modem.

UPDATE: My ISP (AT&T) says a 12 year old modem should have no problem working with any new routers. The modem is pass through (no bridges) and I set the static IP in the router (just like I have done previously). However, the tech support person said make sure the VP is set to 0 and not the default 8, and the VC is set to 35 (that is the default).

I'm not sure what those reference, but I can go through the router's manual set-up and see if that shows up somewhere. I'll give it a try when there is time and share the results.

In any case I will talk with my ISP and see if I can get more details and let you all know.

VP aka VPI aka Virtual Path Identifier
VC aka VCI aka Virtual Channel Identifier

you must have a dsl modem.

I had a horrible time getting an aftermarket modem to work on my dsl. There are sooo many settings and most of them will cause complete failure to connect, making initial setup very difficult if you're not using a model of modem they have a cheat sheet for. And they can use different terminology from modem to modem, or have some things hidden and unchangeable, making copying settings to a different model of modem very challenging.

My dsl modem is also set up passthrough as I have a static block of 5 (8). I have a switch after that which feeds a few static mapped machines, and also a router that provides NAT/DHCP for my LAN.

Setting up the router on the other side is downright trivial compared to getting the dsl modem to be happy. There's close to zero chance of an incompatibility.

No less than AirPort Utility.app uses that terminology (at least wrt to configuring my Time Capsule), in its Internet panel's options...

Code:

( Internet Connection )

Select if you want this Airport wireless device to share a single IP address with 
wireless clients using DHCP and NAT, distribute a range of static IP addresses 
using only DHCP, or act as a bridge.

Connection Sharing: [popup menu^]

...and that popup menu contains these three choices:

Code:

Connection Sharing: Share a public IP address
                    Distribute a range of IP addresses
                    Off (Bridge Mode)

I do have a DSL (ADSL) modem. According to AT&T it is straight pass through.

I did a cursory check on the router set-up side and did not see VP or VC settings, but now that you have provided the full names, I'll see what's there. Thanks.

Remember that the initial problem was the new two band router could not see the old modem.

To go back to the original question about whether a static IP is "better" than a dynamic IP, it depends on what you plan to do.

For normal Internet activities--browsing, email, playing online games, whatever--it makes no difference. The only time it matters is if you plan to run some sort of server, or host online games.

If you plan to run a server, like your own Web or mail server, a static IP address is very nice to have indeed. If you don't have one, you need to subscribe to a service like DynDNS so that the rest of the Internet can still find your Web server whenever your IP address changes. With a static IP address, you don't need to do that.

Be aware, though, that most home Internet providers specifically forbid running a server on home broadband, and may cancel your account or bill you more if they find you doing it.

Thanks for that; it's so important, particularly in view of Lion's inclusion of Server, that I wonder how come I never heard it before.

Combined with this, it gives me a whole new perspective on Lion, i.e. that it's included server software is may be beyond useless to a very large majority of the potential upgraders with whom it is being used as a selling point.

(I'll check with Verizon about my running a server and post back.)

For what it's worth, a phone-answerer at Verizon tech support just advised me that I can run server software over my home DSL connection.

To get back to the original original question, it turns out that the router was not the issue, but the DSL modem and/or the phone line were. To make a long story short, even a new AT&T modem required 1-1/2 hours of telephone tech support.

Apparently only dynamic IP addresses are issued for regular home use. Consequently, the modem set-up assumes this is the case. My static IP address required a bump up to a Level 2 tech (how many levels are there?) who had to trace wiring set-ups on his end, do some voodoo and then verify that my new modem was in pass through mode. He said he gets a call like this once every two or three months and welcomed the variety.

So if you have a static IP address, there could be issues with the newer hardware.