Suggestion: mac address clone

[sky-knight]

No, I had CISCO on the phone.

It's an issue related to the MAC address controls used to prevent a single user node from stealing the entire DHCP scope, the adapter bonding used to fuel DOCSIS 3.0, and what happens when you have two 1:1 NAT enabled clients a little too physically close together trying to talk to each other a little too much.

I've gone over all this before, so I don't blame COX, it's definitely a CISCO thing. Just to further reinforce this, I have a buddy of mine that recently graduated college and started in internship in CISCO's Edinburgh office. He was rather interested in the troubleshooting process I was going through on this issue, so I kept him in the loop and sent him all my notes. He asked a question about it, being an IOS intern, he had access to the code in question.

The next I saw the guy he was still trying to recover from the lashing they gave him. Apparently they thought he was some kind of plant. He's under NDA so he won't say much but he did confirm it's a "bug" in the current implementation. But it's one of those design things that's always worked and now doesn't in very specific conditions. So I doubt we're going to see a fix soon, it sounds like something akin to asking Untangle to stop using Java.

[hescominsoon]

ok so it's a cisco issue then and not docsis is what i'm reading right?

[jgerbrand]

Telus uses a dhcp to assign static ip's. You register your mac with their site and their dhcp server then dishes the ip out.

Shaw here assigns a static ip which on first usage caches that mac address to "lock" the ip to the mac. This caches the assignment for 4 hours unless I call to get it flushed. Hopefully they do this in 15 minutes or so, after their on hold wait as well.

Cloning a mac just makes the transition easier.

We work within the restrictions we're given. Selection of ISPs also isn't that great around here.

[sky-knight]

Yeah static IP's locked via ARP cache is normal for coaxial and dsl based ISPs.

MAC spoofing isn't the "cure" for that. Also, please understand while I know why you want this feature. Untangle uses the MAC address for internal processing. If you start changing it willy nilly, you're actually breeding a rather fundamental issue in the platform.

So in a lot of ways the CISCO issue I've described is similar at least in implication... the platforms are working as designed, but changing that design will mean a rather significant change that we likely aren't going to see any time soon.

As for ISP's that use DHCP to hand out statics... those can all just go away. I won't even use those anymore. They aren't worth the headache and time. Business class connections simply need more flexibility than that. If a customer won't get rid of them, they get to deal with them, and the limitations therein...

Really doesn't matter to me, it causes more issues, which means more tech time, which means more billable time. I just warn people up front.

[YeOldeStonecat]

IMO MAC cloning is a duct tape and bubble gum approach. I prefer to do is the thorough way. I have lots of SMB clients across many states and with many many different ISPs. I'm a reseller of biz accounts of some different ISPs..including cable, thus I work with a lot of the admins in their data centers. The preferred approach, when ISPs do DHCP reservations for static IP accounts, is to call the ISP and have a reservation created for the MAC address of the new device...you read them the MAC of your new router..and they do the reservation for you. You leave your WAN set to obtain auto...and presto..there's your static IP..time after time.

In those rare cases where you have to swap/replace routers for some reason, and you need to get online NOW with the static IP...and your ISP cannot setup your DHCP reservation fast enough for you...the solution is still wonderfully simple and accepted...simply setup your WAN with the static info....type in the static IP, subnet, and gateway. Once the ISP has your reservation done for you...if you wish, next time you're onsite, you can change your routers WAN setting to obtain auto. Or just leave it static..there's nothing wrong with that..you're not going to cause any problems.

Either of those two approaches is actually EASIER for the tech...less time invested by you, and more reliable.

[hescominsoon]

Stone you are describing static dhcp..it doesn't matter how it's lipsticked over..that's what it is..and that approach is just lazy.