Adapter before the Router/Comcast Warning Letter

Posts: 20 · Posted: Mon Jun 07, 2004 2:48 pm Post subject:

Just an FYI for some of you who may get letters like this in the future...

I used to work for Comcast and before that for VOL and in both companies we saw this problem. To understand what the ISP is seeing, you have to know that your cable modem has a unique identifier (like a MAC address for those of you who know the term). The ISP monitors for a situation where their DHCP server has two or more IP addresses assigned to a single cable modem and then sends out the letter. There are a lot of very common problems that can occur on the ISP side however that would produce a false positive for this scenario. In other words, they might think you have two IPs when in fact it is not the case. Comcast has obviously decided to justs end out the letter and not worry about false positives, probably because they think they are not getting many. If you get a letter, I would just call tech support without making any changes and ask them to check how many IPs you are using right that minute. If they see only one, then you are probably fine. If they see more than one, you may have an issue.

Posts: 5 · New Forum Member Joined: Jun 08, 2004 Posts: 5

ASPWebSmith wrote:

Just an FYI for some of you who may get letters like this in the future...

This doesn't make much sense on their part. If they want to restrict customers to one IP address... then they should simply be able to configure their DHCP servers to only lease one IP address per unique cable modem. (Similarly, if you buy 2 addresses... then lease 2).

It sounds like either (1) they messed up and didn't configure correclty, and now need to fix it, or (2) they intentionally leased out the extra IP addresses so they could try to sell you the second one or their networking option.

Posts: 64 · Posted: Mon Jun 07, 2004 8:13 pm Post subject:

johnmagee4 wrote:

This doesn't make much sense on their part. If they want to restrict customers to one IP address... then they should simply be able to configure their DHCP servers to only lease one IP address per unique cable modem. (Similarly, if you buy 2 addresses... then lease 2).

It sounds like either (1) they messed up and didn't configure correclty, and now need to fix it, or (2) they intentionally leased out the extra IP addresses so they could try to sell you the second one or their networking option.

Thanks for writing that, it's how I feel too. I tore apart my entire system when nothing was wrong in the first place and Comcast CS wasn't able to give me any information at all, they couldn't even tell if I was using two IP addresses when I called.

Posts: 20 · Posted: Tue Jun 08, 2004 9:07 am Post subject:

I am not trying to defend Comcast here, g-d knows I have had my share of issues with them, but I think it is important to remember when dealing with a major ISP or any large IT service provider (like a certain Voip company) that these services require huge networks made up of thousands of computers, routers, servers, switches, etc and adminstering all these devices is very chalenging. Most of us probably have only one or two computers at home and maybe one router, yet I'll bet everyone of us can remember at least one situation where we accidently misconfigured something and brought down our entire system. And I gurantee the stuff your using at home is a lot easier to take care of than the stuff Comcast ahs to use to support their millions of users. With the constant upgrades and patches and every 13 year old computer wiz in the country trying to hack their network, I think you can see how it might not be quite as simple as we imagine to configure there system to just not give out multiple IPs. Having worked for several large ISPs, I can assure you that most of the people involved are seriously commited to providing a quality service, and I urge you to remember that the next time you call tech support. Thanx for listening.

Posts: 64 · Posted: Tue Jun 08, 2004 11:19 am Post subject:

ASPWebSmith wrote:

I am not trying to defend Comcast here, g-d knows I have had my share of issues with them, but I think it is important to remember when dealing with a major ISP or any large IT service provider (like a certain Voip company) that these services require huge networks made up of thousands of computers, routers, servers, switches, etc and adminstering all these devices is very chalenging. Most of us probably have only one or two computers at home and maybe one router, yet I'll bet everyone of us can remember at least one situation where we accidently misconfigured something and brought down our entire system. And I gurantee the stuff your using at home is a lot easier to take care of than the stuff Comcast ahs to use to support their millions of users. With the constant upgrades and patches and every 13 year old computer wiz in the country trying to hack their network, I think you can see how it might not be quite as simple as we imagine to configure there system to just not give out multiple IPs. Having worked for several large ISPs, I can assure you that most of the people involved are seriously commited to providing a quality service, and I urge you to remember that the next time you call tech support. Thanx for listening.

I really appreciated your information, mostly I was wishing you still worked for them!

My problem with Comcast is that they took over AT&T here (Mpls/St Paul, MN) and cut the staff drastically, CS seemed to suffer the most. Then, they raised prices several times, not to mention the fiasco when they switched everyone from attbi.com email addresses and wanted us all to install spy-ware type software that took ownership of IE too. They're still getting a $150 a month from us for broadband/digital cable, just not the $40+ for phone service (no long distance), which also was a type of Voip.

Posts: 35 · Posted: Tue Jun 08, 2004 2:25 pm Post subject:

(my apologies if this is on here twice, I thought I hit submit but can't see my post)

Lets play "what if"...

What if, when one unplugs their PC from the cable modem and then plugs in their MTA, that Comcast leases another IP for the MTA's MAC address. Further, what if after that has been done one does some troubleshooting and plugs their computer back in (getting the old IP address that was already leased to the PC, if it had not expired), then the MTA, etc. PERHAPS Comcast's DHCP servers thought these devices were online at the same time considering they had concurrent IP address leases. PERHAPS this is Comcast's mistake.

If I got this letter, I would reply to Comcast stating I needed the exact date and time that these devices were concurrently operating on separate IP addresses. It may coincide with when you first got Vonage and were playing with it. In which case, it would be my guess that the problem has already been taken care of.

Perhaps. Also, perhaps I am full of s**t. Who knows?

Posts: 64 · Posted: Wed Jun 09, 2004 1:33 pm Post subject:

AD8BC wrote:

What if, when one unplugs their PC from the cable modem and then plugs in their MTA, that Comcast leases another IP for the MTA's MAC address. Further, what if after that has been done one does some troubleshooting and plugs their computer back in (getting the old IP address that was already leased to the PC, if it had not expired), then the MTA, etc. PERHAPS Comcast's DHCP servers thought these devices were online at the same time considering they had concurrent IP address leases. PERHAPS this is Comcast's mistake.

If I got this letter, I would reply to Comcast stating I needed the exact date and time that these devices were concurrently operating on separate IP addresses. It may coincide with when you first got Vonage and were playing with it. In which case, it would be my guess that the problem has already been taken care of.

That senario sounds the most fitting of all, but no one at Comcast CS/Tech could give me information as what day/time we were showing 2 IPs, and they also couldn't tell me if we were showing 2 at the time I called. Their only advice was to wait until the deadline date on the letter and see what happened (nothing happened of course).

Quote:

Also, perhaps I am full of s**t.

Nope - yours is probably the only explanation. A Vonage tech thought that's what happened too.