Unable to contact DHCP server. cannot retrieve IP address (Router recommendations)
 

I have a new connection. And two laptops. I connected one first, directly to the modem using NTL CD. It did work fine. One thing that happened, is some of my pro application that use FLEXLM licences stopped working because MAC address on the Ethernet cad was changed. !!! Why is this happening?

Anyway, I then tried to connect the second laptop with the same cable and after some trouble it did work.

But the first one does not want to connect anymore? Any ideas why? I have tried resetting, restarting (both PC and the modem) but to no avail.

It is running WinXP Pro. I tried checking things using ipconfig and noticed that my DHCP client was switched off. OK, I enabled it.

ipconfig lists the address 169.254.88.93, it can release it to 0.0.0.0 but cannot renew it saying that it cannot contact the server.

The tech support is not very helpful. The recommended restart and then said I could refresh IP setting by running

netsh int ip reset resetlog.txt

Which did not help.

Any ideas what could be wrong. Or what I could check or try?

It seems NTL software messed up this machine as the other one can still connect just fine.

Thanks a lot

Re: Unable to contact DHCP server. cannot retrieve IP address
 

You shouldn't need the NTL CD if you are connecting via Ethernet. Also, there isn't anything on your CD that should be able to change the MAC address on the PC. You *can* change it via windows, but in general, you won't have a reason to do this.

Also, are you connecting to the net via a Set Top Box or Cable Modem? It sounds like you are connecting via Cable Modem. If so, you need to unplug the modem from the mains every time you connect a different PC. In the long run, it is far easier to buy a router if you plan to use multiple PCs on one connection.

Regarding your FlexLM problems, well, do you connect to a licence-server? If so, where is it? If it's at work, there may be a firewall preventing you connecting to it. Our FlexLM server at work is behind a firewall, so I can connect to it freely at work, but if I need to connect to it from Home, I have to go through a Virtual Private Network we have set up at work.

:welcome: to CableForum BTW.

Re: Unable to contact DHCP server. cannot retrieve IP address
 

OK, set by step:

Thank you.

It is a cable modem. Switching it off at the mains is a good suggestion but does not seem to work reliably. Since my last post I have managed to make the machine that I was complaining about to work (I do not see how, it was refusing to behave since yesterdayâ₠¬Â¦) but now the other one is not able to retrieve an IP address. I am thinking of getting a router but am not sure which one. The one NTL recommends seems to be an overkill with ASDL functions and is expensive.

About MAC address. It HAS changed. I am not mad. I am using a variety of programs that rely on MAC addresses for licences regularly and it is the first time I see it. I have changed it back now. I generally do not understand why it happened and what (if any) is the relationship between the Ethernet cardââ‚ ¬Ã¢â€žÂ¢s MAC address, the modemââ‚ƚ¬Ã¢â€žÂ¢s MAC address and IP assignments.

FlexLM. I have both local and remote licences. And I am using VPDN for remote access. The licensing problems are due to the changed MAC address, that is for sure. I have been able to have an alternative license issued for two programs for the new MAC and they do work.

Configuration. I would rather not use that CD at all. But I could not connect and was trying all options. I have the relevant services disabled anyway now that I am connected again. If you could let me know how I can de-install all this stuff cleanly but still have the connection working I would be grateful.

VP

Re: Unable to contact DHCP server. cannot retrieve IP address
 

You've *got* to power-cycle the modem when swapping devices or you'll get exactly the symptoms you're describing.

No idea on the MAC changing, unless there's some virus around that does it.

NTL (for cable modems) don't care about your ethernet card's MAC. The modem's mac is stored against your account details. The IP address is given to your MAC, often for quite long periods. Changing your Ethernet card's MAC results in a change of IP.

Re: Unable to contact DHCP server. cannot retrieve IP address
 

Are they network licences? If they are, then the only time FlexLM uses a Mac address is that it needs one for the server which is serving the licence.

Re: Unable to contact DHCP server. cannot retrieve IP address
 

Aha. Thanks again. I am very glad this forum is an active place. NTLââ‚Âà ‚¬ÃƒÂ¢Ã¢â‚¬Å¾Ã‚¢s tech support folks are tricky to get the information from and expensive to talk to (I have no landline).

OK, it is clearer on the MAC addresses. Still strange mine has changed. I am virus-clean to the best of my knowledgeââ‚ ¬Â¦ And how come on one hand you are saying they only register the modemââ‚ƚ¬Ã¢â€žÂ¢s MAC address and on the other the change of the Ethernet cardââ‚ ¬Ã¢â€žÂ¢s address will result in a fresh IP assignment?

In case of FlexLM, well my machine is both the server and a client in two cases. The licensing utilities specifically request a MAC address at the time of a licence issue and the licences cut by the vendors include MAC addresses in the textâ₠¬Ã‚¦

Any suggestion on the router front? I know it is supposed to be for a different forumââ‚ƚ¬Ã‚¦ But as we have already started hereââ‚ ¬Ã‚¦ I have long cables and could go wired if it works OK and is considerably cheaper. Also, what happens with IP addresses if one uses a router? Will the two machines get two addresses from the NTLââ‚Âà ‚¬ÃƒÂ¢Ã¢â‚¬Å¾Ã‚¢s DHCP server?

And about that clean de-install? Can I just de-install the client the doctor from remove Programs? Will this break the connection? Is there something else that needs removing? Or should I better leave things as they are?

VP

Re: Unable to contact DHCP server. cannot retrieve IP address
 

The MAC address of the modem identifies it uniquely and is assigned to your cable line when the engineer installs it, hence the reason that ntl cannot send out replacement modems by mail. An ntl modem will only work on the connection it was registered to.

Regarding the router, wired ones can be bought for £20, I have an ORIGO 4 port router which cost £15.99 + VAT and has been brilliant.
The router assigns IP addresses automatically when set to DHCP, the modem IP address remains fairly static and is assigned by the ntl server, mine hasnâ₠¬Ã¢â€žÂ¢t changed in months.

Re: Unable to contact DHCP server. cannot retrieve IP address
 

True.. It's also embedded in the large block of licence code (the blocks of four or five characters)..

You may be able to change the mac address back yourself. Not all network cards support this, but try this:

Go to "Network Connections", then right click on the network connection. Under the words "Connect Using", Windows shows the name of your Network Card (note, it may show the name of the chipset the card uses). Next to this is a large "Configure" button. Click this.

Now click "Advanced" and then look for a property named "Network Address" (or something similar). Either click "Not Present" (which should reset it to the default) or type the old Mac address into the "Value" field.


Have a look at http://www.cableforum.co.uk/forum/article.php?a=74

Re: Unable to contact DHCP server. cannot retrieve IP address
 

Thanks - it is a working trick, as I mentioned I had done this already.

As for the routers, again - thank you. I have seen that page before but was hoping for extra wisdom maybe. E.g. here in the university lots of people are coming and going and it is usually possible to pick up all kind of second-hand gear. But it is tricky to know what will fit. E.g. are ASDL modem/router combos any good? Like this one

Netgear DG834G
http://www.netgear.com/products/details/DG834G.php

Or do cable setups require a different kind of beast?

Thanks,

VP

Re: Unable to contact DHCP server. cannot retrieve IP address
 

You do NOT want an ADSL router - it will not work!, you need a router with an Ethernet connection to your STB, NOT a phone line connection.

Re: Unable to contact DHCP server. cannot retrieve IP address
 

US Robotics Broadband DSL /Cable Router + 4X 10/100
£22.45 inc VAT

http://www.ebuyer.com/customer/produ...duct_uid=97602

Re: Unable to contact DHCP server. cannot retrieve IP address
 

Cable ISPs have an Ethernet presentation, so you only need an Ethernet WAN port. ADSL ISPs typically don't provide a separate modem, so you often find the modem and router built into the same box (I have one on my ADSL line). This is what's usually called an ADSL/Router. It's useless on cable, though, since it expects the WAN presentation to be a phone socket, so don't get one. Get a standard Ethernet router as suggested above.

Re: Unable to contact DHCP server. cannot retrieve IP address