Joho the Blog
An Entry from the Archives

I'm not a network admin (but I did stay at a Holiday Inn last night), and for what it's worth, I think you have it exactly right. They may be able to snoop your private network, but there's no reason they should care if your internal devices are static or not.

I have been a network admin, and they're full of sh*t. If she has access to the router, she might be able to tell that you're using a static IP address, but the 192.168.1.x addresses are only used on your private network (between you and the router).

There is a special case: I have experienced ISPs in third-world countries who use non-routable 192.168.x addresses internally in their network. But in that case your router would also have a private address on its outside.

It's also possible there was some confusion between you and the tech person. Now, if she thought you meant that you were setting a static IP *for the cable modem*, I could see where she would say it would turn off. But I don't see how anyone could even tell if the IP assigned to a computer behind the modem was static or not. And of course it doesn't matter one iota if your computer's IP is a static 192 address or one handed out by the modem.

A lot of ISPs still assume that you have one computer in your household and your cable modem is plugged directly into it. Thus the phrasing of their warning refers to "your computer".

My guess is they only care about their own IP addresses in which case they'd only care about your router's external IP.

If you tried to give your router a static external IP address it might cause the problems they are talking about.

Let me repeat that I was 100% explicit and careful about where I was setting the IP. In fact, I repeated so often that I wasn't setting it on the RCN modem but on my router that I bought and plugged into the RCN modem that she got (understandably) impatient with me. It was at that point that she started reading to me the list of machines that my router was serving. So, she may have been wrong, but I don't think she was confused.

The modem doesn't get an IP address it's just a link device like a network card, it has a MAC address. If you were telling her that you were setting a static IP on your router she could have easily interpreted that as if you were giving your router a static EXTERNAL IP. Then she would have cause to warn you.

The router must accept a dynamic address from their DHCP server on its external interface. On the internal interface of your router and the rest of you network it shouldn't matter.

Of course it's entirely plausible that she was applying the "no static IP rule" without really understanding why and hence applying it too broadly.

I'm going to join everyone above who responded, and summarize: YOU are not the one who was exposing ignorance about setting a static IP address in this situation!

You've just discovered why we need strong network neutrality laws.

Or not, I don't know.

Maybe she believes your router is configured as a DHCP server and will shut off if it finds a static IP address in its range?

Maybe this is simply a trivial configuration issue and not an overreaching "Thou shalt not have a static IP address" edict.

Key question - what were you trying to do that prompted the call to tech support? That is, how did the topic come up? (we may be missing a part of what led to the misunderstanding).

I called because I was getting no ping, and multiple power cyclings of the modem and router didn't help. The support person discovered that my modem (well, technically their modem) wasn't showing up on her end. She pushed some button and then could see it. The outage became an innage.

You and the tech support girl had a failure to communicate. They don't have a magic finger that lets them go inside your private network and peer into your 192.x.x.x nodes. Don't worry, be happy.

While I agree with the analysis of most of the replies above, (the rep was wrong), I encourage you to assign as the static address for your computer one of the higher numbers. When your router hands out addresses via DHCP, it will most likely start with low numbers (192.168.0.3 or 4), and then work its way upward. The highest number is 192.168.0.254 (assuming that the subnet mask is 255.255.255.0), so if you assign your computer one of the higher numbers, you minimize the possibility of an IP address conflict which could occur if the same address was assigned both dynamically and manually.

I'm a little weirded out by the fact that she could list off the machines within your network that the router was assigning IPs to. Maybe I'm not understanding correctly, but I thought that information was only available outside your home network if you have SNMP enabled and she had the connection information. Otherwise, shouldn't all traffic appear as coming from a single device: your router?

Lose RCN and go with Speakeasy. They are more expensive, and it's slower because it's aDSL, but their tech support staff actually knows stuff.

1. I'm pretty sure she identified the machines using my router via their MAC addresses. I was disturbed by the fact that RCN's little fingers were probing my network orifices.

2. Thanks for the suggestion that I assign higher rather than lower static numbers. That's what I do, but I didn't know why.

3. I like a lot of things about SpeakEasy. But I'm getting 20MB down from RCN. (Well, I'm paying for 20MB down and usually get 13MB or so.) Also, SpeakEasy.net doesn't think I'm in its service area.

Hello, I've been wanting to setup a personal web server from home. I've change isp to time warner cable because I was told their service comes with static ip and they don't block port 80.
My problem is how do I obtain "my" service information;static ip #,subnet mask#,gateway#,and the dns1-3 #'s. I've called time warner and asked for my info only to be redirected to linksys support where there they tell me I must obtaian all this info from my ISP.
How do I go about obtaining this info so that i can configure my linksys router?

It's one hell o of an education.
It's apparent that to obtain a static ip, one must upgrade to commercial business or even rewire the shack (apartment)to sustain a much higher (stronger) level of internet service?
Im just trying to tie my registered .com name(domain name)to an apache server (2nd pc)to publish (expose) pages on the world wide web.
Is there any legal dns hack I can execute?

When forwarding my domain name I must put in a static ip or server name right?

Any help on static ip is truly appreciated at this time.
Any recomendations besides paying $omeone else for hosting?