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Network config question

Comcast cable runs their entire cablemodem network on DHCP. Even the five "static" IP's that I'm paying a premium for. I'm drafting a letter to the head of their broadband division politely requesting that they put their "Pro" customers on static IP's like the rest of the civilized world.

Out of curiosity - off a best guess regarding their network setup, how tough would it be to change the small percentage of customers on their Pro plan from DHCP to Static IP's? (customer equipment migration issues aside)

I just want to know what I'm asking them to do before I ask them to do it.

Philo

Philo
Saturday, October 18, 2003

DHCP and Static IP addresses are not mutually exclusive concepts. I get my static IP address via DHCP. It's always the same.

On the bonus side, using DHCP not only configures that static IP address, but also gets to bring along all the things that DHCP can bring along like DNS servers, that may change over time. The admin effort is much lower if EVERYBODY is on DHCP, even those who will always get the same static IP address.

Brad Wilson (dotnetguy.techieswithcats.com)
Saturday, October 18, 2003

Running a mail server on DHCP means you can't send email to a significant percentage of people online, thanks to overly zealous DNSBL's

Maybe I just need to get them to register the dynamic IP's in ARIN properly.

Philo

Philo
Sunday, October 19, 2003

"Maybe I just need to get them to register the dynamic IP's in ARIN properly."

That seems more likely your problem.  If you're receiving a static IP from the DHCP server then that's technically no different than if you typed it in yourself.

Almost Anonymous
Sunday, October 19, 2003

"Maybe I just need to get them to register the dynamic IP's in ARIN properly."

Agreed.  If you're getting the same DHCP-allocated address every time, it makes no difference if you typed it yourself.  They won't care.

But if the reverse lookup is blacklisted or missing, that can be a problem.

-Rich

Rich
Sunday, October 19, 2003

Ah, being on DHCP has nothing to do with your complaint. The problem is that comcast provide no way for other systems to spot what is dynamic and whats static.
There a few lists on the net that cover this.
pdl, dynablock.easynet.nl, maps has one as well.
AOL ask the larger ISPs to say which IPs should be sending out.
I suspect what you're asking for may be impossible. My corporate ISP splits the business lines off from the consumer and SWIPs the IP addresses over at RIPE to the companies concered and gives us proper reverse DNS.
However if your static IPs are in the middle of a block of consumer IP addresses (quite likely) you'll never escape.
One possibility is to get a secondary mail server (or if you colo your website use that provider to smarthost) if you don't trust comcasts smart hosts on the way out.
I haven't heard of many folks blocking sending mail to dynamic IP addresses just receiving mail. The whole thing is a reaction to badly configured proxy servers and trojaned users on windows machines.

Peter Ibbotson
Sunday, October 19, 2003

You want static IP's, you pay for it.

You give them the MAC addy of your gateway, DHCP will give you those addressse on connection.

fw
Sunday, October 19, 2003

This is off topic, but my provider doesn't guarantee static IPs, yet I've never seen my change...  I found that rather surprising, but an added bonus I guess.

christopher baus (tahoe, nv)
Monday, October 20, 2003

fw, to clarify - I *am* paying for "static" IP's. Comcast has a "Pro" service that doesn't block VPN, gives five "semi-permanent" IP's, and removes the "no server" clause from the TOS.

Since I can't get DSL, and a T1 is $800/month, it's my only option. (though I'm starting to look into colocation because this is getting so silly)

The thing that annoys me is that they *could* provide static IP's, or at least give the "pro" customers IP's from a properly listed ARIN block. But they don't bother.

So I'm going to try shaking the trees a little.

Philo

Philo
Tuesday, October 21, 2003

Philo, which lists do you find yourself in?
http://moensted.dk/spam/ has a handy dandy checker.
http://www.declude.com/junkmail/support/ip4r.htm
is also worth while.
I assume that the saintchad.org IP address is the one your talking about. As far as I can see it's on the easynet dynamic list. Should be possible, the easynet folks seem to think that certain rDNS and biz.attbi.com are about comcast "business" lines. Wirehub also list you as being dynamic but I think it's the same list as the easynet.nl one so getting removed from one should fix the other.
You're not on the AOL list.
Most of the other block lists on that page ain't worth worrying about (They're either VERY extreme or like the UUINTRUDERS list will punch holes if you really need to talk to them)

Peter Ibbotson
Tuesday, October 21, 2003

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