Problems getting an IP address with a Netgear router [Archive]

sjdigital

11-07-2009, 08:15

I have a Netgear DGFV338 wireless router that doesn't seem to agree with the Virginmedia cable internet system. I'm now on my third router, the first two having been replaced by Netgear under warranty, and on my second cable modem, but all to no avail.

If I connect my router to the modem, boot up the modem and then boot up the router I don't get an IP adddress from the modem. If, however, I then reboot the modem without disconnecting or switching off the router, I do finally get an IP address. But I can't rely on it continuing to work as on three occasions it has simply lost the connection and nothing I can do will bring it back. It was on those occasions that Netgear replaced the router but it's hard to see that three different routers could have the same, unspecified problem.

I did talk to one very helpful guy in Virgin media Tech Support last week who said that he was aware of some similar problems with certain Belkin routers that had some sort of conflict with the Virginmedia system but he was not specific as to what it was. Any further calls to tech support have ended up in the Indian call centre - 'nuff said!

Has anyone any ideas what the problem might be? And if not, any advice on how to try and get through to a knowledgeable tech support guy in the UK?

Cobbydaler

11-07-2009, 08:25

That's an ADSL modem router:

http://netgear.co.uk/wireless_firewall_dgfv338.php

You need something from e.g. this page:

http://www.netgear.co.uk/home_wireless_cable_routers.php

sjdigital

11-07-2009, 08:57

While I do appreciate you taking the trouble to read my post, and offer your suggestions, how do you think I have been able to connect my router to the modem and get an IP address if it's just an ADSL modem router????? Have another look at your linked page.

Cobbydaler

11-07-2009, 09:03

Sorry, missed the ethernet WAN port...

Dai

11-07-2009, 09:54

Without knowing anything about the router or RTFM my first though was perhaps by default it's looking at the ADSL port for an IP rather than the fall-back port.

It may be worth looking at the router setup pages to see if there's any sort of switch you can set to define WAN RJ45 port as primary.

skii

11-07-2009, 12:07

sjdigital

11-07-2009, 15:50

Hmmm...3 Routers 2 Modems and you still have not learnt a lesson.
By any chance did you tell Netgear you was using a ADSL Router
on a Cable connection????....NO? ,bet they would have said no to a replacement,and told you to Swivel mate.

Thats why there are dedicated types of Routers try getting the correct type
makes life easier.:dozey::(:confused:

Skii

One of the things I find so intriguing about internet forums is why people feel it necessary to be so rude and abusive when someone asks for help. I guess it's the cloak of anonimity that allows them to act the tough guy when they actually have no idea what they're talking about.

But to address your unhelpful comments, yes, I have learnt a lesson from three routers and two modems - the lesson being that the problem is almost certainly not a hardware one, but probably a system one that I'll need to follow up with Virginmedia. Hence my original post.

And if you think about if for a minute (which obviously you didn't), Netgear are not going to simply send me two replacement routers without trying to find out what the problem is. In both cases I had lengthy discussions with their helpful tech support and we went through all the possible configurations of the DGFV338 when used with a cable modem.

So in fact I do have a router that is correct for the job in hand: it just happens to be able to operate as an ADSL modem and router as well. But I guess that's too difficult a concept for you to grasp.

Any more helpful ideas?

@DaiNasty

The router is set to use the Ethernet WAN port and the settings haven't changed at all. It just sometimes loses the connection. Until recently I couldn't ever get it to reconnect but it now seems that rebooting the modem without switching off the router does the trick although I can't be sure that that will always work. And logically it shouldn't anyway.

Ben B

11-07-2009, 16:10

Did Virgin Media not give you a router which you could try to see if the same issues occur with that one?

Peter_

11-07-2009, 16:26

Did Virgin Media not give you a router which you could try to see if the same issues occur with that one?
Not all packages come with a router as part of the deal.

sjdigital

11-07-2009, 16:29

By way of further explanation, I should have said that when the problem arises, I simply connect up my faithful old Linksys router and everything works just fine. But plug in my Netgear one once more and it cannot get an IP address from the modem, unless as I have recently discovered I reboot the modem without rebooting the Netgear, which goes against all received wisdom in such matters.

bubblegun

11-07-2009, 16:29

Peter_

11-07-2009, 16:36

When you got the new modem did they send you the correct power pack?

My parents had a similar issue and they sent a new power pack which seems to have fixed the issue.

It seems daft that virgin replace old modems with new but don't replace power converter.
Every new modem comes complete with a new power pack on the Cable side as the power packs are different to ones on the older modems, and they come complete modem and power pack in a package.

sjdigital

11-07-2009, 16:57

bubblegun

11-07-2009, 17:11

Every new modem comes complete with a new power pack on the Cable side as the power packs are different to ones on the older modems, and they come complete modem and power pack in a package.

Mine didn't and neither did my parents. My old modem is a 12v input and the new one says 10v but they said it didn't matter.

Peter_

11-07-2009, 19:19

It was an identical modem, complete with new power adapter, but I just used the old power adapter as it saved grovelling on the floor to replace it. But if that might be an issue, I'll replace it and see what happens. Interestingly, the Netgear tech guy said the same about the power supply for the router so I did use the one that came with the latest replacment router. Thanks for the suggestion.
You should always swap the power pack even if it was the same modem.

---------- Post added at 19:19 ---------- Previous post was at 19:17 ----------

Mine didn't and neither did my parents. My old modem is a 12v input and the new one says 10v but they said it didn't matter.
Are you on ADSL Virgin National as every Cable modem comes with a power pack and you should not be using a power pack of a different voltage any agent who said that wants reporting.

skii

11-07-2009, 19:39

sjdigital

11-07-2009, 19:46

You should always swap the power pack even if it was the same modem.

Good point, and I've grovelled on the floor and done so now, so let's see if it holds the connection. But nonetheless, it's a strange problem. Why would the modem connect without any problem with one type of router, and have so much difficulty with another one?

Peter_

11-07-2009, 20:17

Good point, and I've grovelled on the floor and done so now, so let's see if it holds the connection. But nonetheless, it's a strange problem. Why would the modem connect without any problem with one type of router, and have so much difficulty with another one?
It can happen and I would stick with the one that works, as for rebooting the modem and not always the router, that is fine as the modem learns the MAC address of the last item it was connected to, so to clear the memory you have to reboot it.

sjdigital

11-07-2009, 21:16

But the basic problem is that if I follow the conventional routine of boot the modem, then the router, the router can't get, or isn't given, an IP address by the modem. But if I then reboot the modem again while leaving the router switched on and connected, the router then generally gets its IP address and all is well, until the next time. Any ideas as to what is going on?

sjdigital

13-07-2009, 12:54

Soooo.still not learnt dedicated Routers BUY ONE and that will be end of your
problems.So you had long disscussions with Netgear help???,hmmmmm seems
they need a kick up the ass!!!!.Or are you too tight to spend £30 on the correct router.
Buy the correct equipment then you might not get a short and to the point post.....

Skii...:angel:

So far all you've posted is nonsense, so I can only conclude that you know bugger all about the subject! But just to humour you, my router is a dedicated one; it just happens to be able to be a dedicated ADSL modem and router as well as a dedicated Ethernet router (although not at the same time). And I can assure you, it cost a damn sight more than £30!

And why exactly do you think that the Netgear Tech Support guys need a kick up the ass when you were not party to my discussions with them and therefor have no idea what we discussed and what options we tried. But clearly you must feel you know what the answer to the problem is so why not share your wisdom with the rest of us? I can hardly wait to find out how to solve my problem and you seem to the the only one who knows.

Dai

13-07-2009, 13:42

It's certainly a strange one. Have you checked to see if there's a firmware update available for the router? Since this is recent exchange kit you probably have the latest but it's worth a look.

Other than that no ideas. In your situation I'd probably eBay the router and buy a different model. But I'm impatient that way.

silverwolf_uk

13-07-2009, 16:10

It's certainly a strange one. Have you checked to see if there's a firmware update available for the router? Since this is recent exchange kit you probably have the latest but it's worth a look.

There is a fairly recent firmware update for this modem dated 28/04/2009 here ---> http://kb.netgear.com/app/answers/detail/a_id/8098/session/L2F2LzEvc2lkL1c0anZkS0Nq

Cheers,
Wolfie.

sjdigital

13-07-2009, 22:52

Thanks for the suggestions guys, but I am running the lastest firmware, at least for the Ethernet router side of things. I haven't bothered to update the ADSL firmware as I don't use it and the Netgear tech guys didn't think it was relevant. But I'm confident that Skii will come up with the answer - he seems to be such a knowledgeable sort of guy, doesn't he?

Visitor

13-07-2009, 23:55

Have you tryed a fixed IP address instead of auto ?

sjdigital

14-07-2009, 07:38

Have you tryed a fixed IP address instead of auto ?
The problem isn't getting an IP address from the router, where a fixed IP address would be an option. The problem is getting a public IP adddress from the Virgin Media network via the cable modem. A fixed IP address isn't an option in this case.

Visitor

17-07-2009, 11:23

I use the Netgear WPN824V2, Ive also plugged in the free router from Virgin Media (A Netgear 54 speed), nothing to set, they both worked out of the box without having to set anything.

So the guess is that since your modem does have ADSL, its going to need a lot of manual settings. Perhaps the things that are on auto like your real IP address, The MAC address of your modem etc, and your local IP address (192.168.1.3)

Use ipconfig and get as much of the info as you can, then try the settings manually. If there is a conflict, switching on the modem first, will give a new setting to your router, if its all on auto, sounds like its not getting new info

sjdigital

17-07-2009, 12:08

@Visitor
I'm not sure I understand what you are suggesting. Just because the router has dual ADSL and Ethernet capability doesn't mean that it requires any more manual intervention that a dedicated one other than to set it to either ADSL or Ethernet. Once that is done it's just like any other router. It is obviously set up to work with the cable modem as I am able to get a public IP address on it at the moment, but then for no apparent reason it may lose the IP address and cannot reconnect to the modem.

Don't forget, the router doesn't ever get a 192.168.1.x address from the modem - it gets a public IP address from VirginMedia, in my case in the range 82.7.x.x. But it will get a 192.168.100.x address from the modem if the the cable connection to the modem is disconnected.

The only solution I have found, and even then I can't be sure that it will always work, is to reboot the modem (but not the router) which might suggest that the problem is with the VirginMedia network rather than a hardware problem at my end since I'm now on my third router and second modem.

But for the moment all is working fine - it's just that I can never be sure when it will fall over and would like to try and get to the bottom of it. That's why I'd like to find a Virgin Media tech support person in the UK to speak to who might actualy know what they're talking about! Anyone know which number to call to be sure of a UK based support team?

A Dave

17-07-2009, 23:07

......But for the moment all is working fine - it's just that I can never be sure when it will fall over and would like to try and get to the bottom of it. That's why I'd like to find a Virgin Media tech support person in the UK to speak to who might actualy know what they're talking about! Anyone know which number to call to be sure of a UK based support team?

Have you considered posting a query on the VM newsgroup system? If you've not used newsgroups before, information on getting started can be found here (http://www.virginmedia.com/myvirginmedia/newsgroups/).
I would suggest posting on virginmedia.support.broadband.cable. Queries posted there generally receive a reply from UK based VM Technical Support agents.

sjdigital

18-07-2009, 09:10

Thanks, that sounds like a good idea.

Ignitionnet

18-07-2009, 10:24

Those guys might be able to offer more insight into what is being seen at the DHCP server when you try and connect, IE is there some compatibility issue, is your kit NACK'ing the DHCP offer, etc.

sjdigital

19-07-2009, 08:53

That seems a more likely scenario. I'll follow this up as suggested with the WM newsgroup system.

Seems like Skii doesn't have the answer after all!

toady

19-07-2009, 11:01

Ditch the ADSL modem/router and buy a dedicated router for the job
The one you have is not compatible with the cable modems that VirginMedia supply

sjdigital

19-07-2009, 13:37

How would you define a 'dedicated' router?

Sephiroth

19-07-2009, 15:18

I've given the three pages of posts a quick look and it seems that the problem always points back to the Netgear router.

When I first got the cable internet service, I bought a Netgear router (WPN824) and had to fart about with its settings never quite getting there. So it's sitting in its box because I bought the Draytek Vigor 2910 (now superseded by the 2920). After checking that the 2910 was set up for automatic everything it worked straight away.

Unless VM have done something non-standard with your account at their hub or head end servers, the cable modem should serve the IP address to the router.

Hope that helps.

sjdigital

19-07-2009, 15:37

Thanks. I do appreciate it when people offer considered suggestions. And for sure there seems to be an issue between this particular type of router and either the DHCP server on the network or the modem. While I could solve that problem by using one of my spare Linksys routers, I bought the Netgear one to provide a better VPN capabilty than the open source one I had installed on my Linksys and for the eight ports (yes I know I could have bought a switch). So I'll follow up with the VM newsgroup suggestion and see if they can come up with an explanation and a solution. But in the meantime it seems to be working just fine but time will tell!

Sephiroth

19-07-2009, 16:11

Glad it's hangin on in. Another reason I chose Draytek was that it is strong on VPN. You can always keep that option in reserve.

Ignitionnet

19-07-2009, 17:13

SJ. One idea to eliminate the modem entirely - power it off, disconnect the coaxial cable from the back of the modem, power it on, attempt to get an IP lease for the firewall. You should get one in the 192.168.100.0 / 24 range.

It is probably that something about the DHCP lease that Virgin offer isn't to the firewall's liking. An option in the lease it cannot use so it doesn't request, maybe it isn't compatible with a populated GIADDR field (though it really, really, really should be!!) as is required when using IP helpers, maybe it has an option set in the discover which the DHCP server doesn't honour and doesn't respond to the offer the server sends back without this option being honoured with a request.

I would love for geeky reasons to sniff the DHCP traffic and diagnose the issue, but I don't have the time sadly :)

Sephiroth

19-07-2009, 17:37

The easy way of disso;ving anything that might be to do with the Netgear firewall is to turn it off. Windows or McAfee can do the firewall stuff IMHO.

Ignitionnet

19-07-2009, 19:42

The easy way of disso;ving anything that might be to do with the Netgear firewall is to turn it off. Windows or McAfee can do the firewall stuff IMHO.

The firewall will be doing nothing to DHCP, and can't really be turned off given that it's the appliance that OP's having trouble getting to take an IP address. :)

Sephiroth

19-07-2009, 20:46

The firewall will be doing nothing to DHCP, and can't really be turned off given that it's the appliance that OP's having trouble getting to take an IP address. :)
I quote your earlier (complicated) post:

"It is probably that something about the DHCP lease that Virgin offer isn't to the firewall's liking. "

I think you're coming across too jargony (dare I say mumbo-jumbo) to be fully understood by everybody.

Dai

19-07-2009, 21:17

I think you're coming across too jargony (dare I say mumbo-jumbo) to be fully understood by everybody.

Trouble is, when you've exhausted the easy options there really isn't anything left but to look deeper into the bowels of the machine.

I enjoy BB's posts since they usually point me in the direction of things I don't understand but also give me keywords to research.

Ignitionnet

19-07-2009, 21:45

I quote your earlier (complicated) post:

"It is probably that something about the DHCP lease that Virgin offer isn't to the firewall's liking. "

I think you're coming across too jargony (dare I say mumbo-jumbo) to be fully understood by everybody.

Hey,

I appreciate that, but then I'm not trying to be understood by everybody, if that were a concern when I post I'd never get anything posted it'd take too long to explain everything. The posts are for SJ primarily, who is very aware he is using a firewall which happens to also be a dual-WAN router, if anyone else is interested that's a bonus :)

This bit I'll clarify though as I'm having a nice soak in the bath and have a minute.

OP's firewall / router appliance that he is having trouble with may have a rather narrow idea of what a DHCP offer should look like, so when his firewall sends its' DHCP discover out and VM's server responds with a DHCP offer it may not be liking some part of it so doesn't progress the DHCP transaction by sending its' request (DHCP is a 4 step process, client sends DHCP Discover, server responds with DHCP Offer, client either accepts the offer with a DHCP Request which the server confirms with a DHCP Ack or doesn't and the cycle repeats. A simple way to test it is to follow my previous suggestion of unplugging the modem from the coax which will cause the modem to issue a DHCP lease to the appliance, and it will be a bog standard one with nothing interesting about it at all.

If this fails it points to an issue with the appliance itself, if it works fine it points to a problem between the appliance and VM, which depending on how serious the OP is about finding the issue can be investigated further by putting a hub in between the cable modem and the firewall appliance and having a PC running Wireshark connected to the hub along with the firewall appliance to sniff the DHCP conversation off the wire. Once this log is posted here there are a few people who could analyse it.

You have made me think of something though - big thanks for that! ;)

SJ - your firewall appliance isn't running anti-spoofing or blocking traffic from outside on UDP port 67 to its' own UDP port 68 is it?

DHCP clients receive traffic from UDP port 67 to UDP port 68 and they send their responses from UDP port 68 to 67.

Also make sure any anti-spoofing protection is off as DHCP traffic can appear spoofed.

Last but not least DHCP traffic can appear to come from your default gateway which may be in the 10.x.x.x range, make sure you are permitting traffic from your default gateway through. I don't think it should, it should appear to be from a DHCP server as a unicast which is routed by the default gateway with only your outbound DHCP discover proxied but I'm not 100%.

Sephiroth

19-07-2009, 22:13

QUOTE=Broadbandings;34837133]Hey,

I appreciate that, but then I'm not trying to be understood by everybody, if that were a concern when I post I'd never get anything posted it'd take too long to explain everything. The posts are for SJ primarily, who is very aware he is using a firewall which happens to also be a dual-WAN router, if anyone else is interested that's a bonus :).....[/QUOTE]

So why not just turn the router's firewall off (figure 8-8 in the router user guide) to test the theory?

Ignitionnet

19-07-2009, 22:27

Ahhh ok - when you mentioned turning off the firewall I thought earlier you were referring to switching off the whole appliance. I was looking at it as a firewall that happens to be able to route so got a tad confused why you'd want to switch it off :blush:

sjdigital

19-07-2009, 23:00

Thank you all for your many and varied comments and suggestions. I'm not sure I can respond to every one, but let me summarise where I am. The router can indeed get a 192.168.100.x address from the modem when the cable input is disconnected. As for turning the firewall off as per figure 8.8 in the manual, my version of the manual doesn't have a figure 8.8.

And as for anti spoofing, I certainly am not aware of any being run on the router, nor any blocking of ports. It is pretty much 'out of the box' except for setting up my Slingbox.

The problem is that the router can be connected and working (as it is now) but then suddenly and for no apparent reason it loses its connection and rebooting the modem and then the router doesn't work. The only thing that seems to work is to reboot only the modem. When I talked to a very helpful VM tech guy he said that there were instances of the VM DHCP not liking certain routers although in his experience these were generally Belkin and not Netgear.

So not sure what more I can do at this stage until it next falls over and then I can try and get to a VM tech guy. But I will try the VM newsgroup when I get a chance.

Thanks again guys.

Sephiroth

19-07-2009, 23:29

Thank you all for your many and varied comments and suggestions. ...As for turning the firewall off as per figure 8.8 in the manual, my version of the manual doesn't have a figure 8.8.....

It's in the WAN Setup configuration section. You'd check the Disable SPI Firewall item.

Ignitionnet

19-07-2009, 23:39

Sounds like it isn't related to firewalls if DHCP occasionally works. Would be 100% dead otherwise.

Leaves the only other thought that there's a problem with the DHCP client on the firewall.

EDIT: I really should have read the first post more closely!

JadeFalcon

20-07-2009, 02:07

just an idea but have you tried different network cables ? might be a faulty cable

sjdigital

20-07-2009, 07:37

For sure, changing the network cables was one of the first things I tried and it made no difference.

And I still can't find any reference to disbaling SPI Firewall in my instructions. But as the fault is intermittent, this probably isn't the issue anyway I guess.

Thanks again

kpanchev

20-07-2009, 08:35

Ignitionnet

20-07-2009, 08:45

SJ, have you checked the power levels of the modem? By the looks of it, you may have problems with the timings of the communication between the modem and the router. Does the router get a 192.168.100.x IP address every time if the coax cable is disconnected? Also, check the log of the modem, it should give you some idea what is happening...

Modem doesn't log what the DHCP client on the device connected to it does, and there are no issues with 'timings' between modem and firewall / router - if there were power issues the modem would be online intermittently and would be dropping connection on all devices, not just this modem / router.

It would be affecting the ability of the firewall to get online in the first place too, not just its' ability to renew its' lease.

sjdigital

20-07-2009, 20:13

I think at this stage that until the problem resurfaces there isn't much more anyone can do for me. I had thought that perhaps there was an obvious technical issue that those more technically competent than me in such matters would have instantly hit upon. But it would seem that this isn't the case - unless of course Skii is keeping his powder dry and is going to blow us all away with his stunning insight to the problem!!!

So I'll follow up with the VM newsgroups as suggested above and if, or when, the problem resurfaces, I'll resurrect this thread and see what we might uncover when the system is down, assuming of course that I have a way of posting in that event!

Thanks again for all your helpful comments and suggestions.

Visitor

27-07-2009, 10:09

When I first got the cable internet service, I bought a Netgear router (WPN824) and had to fart about with its settings never quite getting there.

What settings, because it works right out of the box, I guess it was too advanced for you :)

Sephiroth

27-07-2009, 11:33

What settings, because it works right out of the box, I guess it was too advanced for you :)
What I didn't tell you was that I also had a pair of Netgear Powerline adapters because the Wireless simply didn't carry to certain parts of the house. That's supposed to woek straight out of the box as well. But it dodn't and Netgear support couldn't solve it.

So I went Draytek, got some different Powerline adapters and all's 100%.

N3m3sis

27-07-2009, 13:42

Hi Sj
I dont know if you have tried this or if it has been suggested to you before, so please forgive me if it has. Have you tried going into your cable modem (192.168.100.1) and disabling the DHCP router built into the VM cable modem? Disable the DCHP on the cable modem, save the settings and restart the cable modem. Whilst it is restarting remove the power from your router whilst the cable modem restarts. When all the lights are on, on the cable modem then put the power cable back in the router and whilst that is powering back up, reboot your pc. You should find that everthing thing then works as it should. And dont always take as gospel what a vm tech tells you. I had this same problem with a friends cable modem and a netgear router that he bought, though he just could not get an Ip address at all. It seems the DHCP function of the some of the vm
cable modems that vm supply, interfere with routers that also have a DHCP function. If you have this issue then you should turn off the DCHP function on the vm cable modem and let the router do the work.
Make sure that the cable from the cable modem is plugged into the "internet" port on the router also (you would be surprised how many people ignore the clearly marked internet port on routers :) ).
If after all that you still have a problem, then clone the mac address of the cable modem on your router.
I really hope some of the above helps and if not then I hope you find a solution.

until the last spent shell falls

n3m3sis

sjdigital

30-07-2009, 23:48

n3m3sis

Thank you for this and apologies for not acknowledging before now but the email notification of your post didn't get to me.

The problem has arisen again and I logged in to the cable modem as you suggested but can't find a way of disabling DHCP. I suspect that is indeed the problem but how to fix it? The modem is a model 256.

But to summarise the problem this evening, the router lost connection with the modem and thus lost its IP address. Rebooting the modem on its own without powering off the router didn't solve the problem as it has done in the past and in fact this time the reboot of the modem forced a reboot of the router, but again, no IP address. But if I disconnected the internet cable from the modem and rebooted it and the router the router got an IP adddress from the modem of 192.168.100.1.

So the problem certainly seems to be with the inabilty of the modem to deliver a network public IP address to the Netgear router. It may indeed be that switching off DHCP in the modem would fix it but there are no options to do anything when I log in, only to view the configuration, status, etc.

And yes, all cables are in their correct slots!

Thanks for your interest. Any ideas how to switch off the DHCP in the modem?

Sephiroth

31-07-2009, 00:55

we never did bottom out the point originally raised by Broadbandings and subsequently taken up by myself. The Netgear router firewall - turning it off.

In your Netgear configuration screen you'll be able to see if the Firewall's on. If so, why not try turning it off. It's in the WAN Setup configuration section. You'd check the Disable SPI Firewall option.

This is so specific to this router (Linksys works OK), I can only think there is a DHCP offer/lease problem in the Netgear..

sjdigital

31-07-2009, 06:42

I realise I may be just dim, but I simply cannot find any option to disable SPI Firewall! I have been through every tab on the configuration page of the router but to no avail! There isn't actually a WAN Setup page as such. Are you sure this option exists for this model of router, DGFV338?

Sephiroth

31-07-2009, 08:39

Sorry, my bad - I was referring to my Netgear Router. I believe in your model the relevant menu is:
Security/Firewall Rules/LAN WAN Rules --> Disable

Yours is a security feature rich router and there may be more to look at.

There is a security event log (Fig 4-21 of your reference manual!!) that can be inspected provided that the firewall is not disabled. Are there any records of interest in there when you try to connect to the internet?

Finally, what is your Netgear router doing with NAT?
Network Configuration/WAN Mode

I have NAT turned off on the Draytek router.

sjdigital

31-07-2009, 09:16

OK, under Security/Firewall/LAN WAN Rules I have the attached. What should I disable?

Sephiroth

31-07-2009, 09:33

OK, under Security/Firewall/LAN WAN Rules I have the attached. What should I disable?

Just click the disable radio button on Outbound and the Inbound configuration screen.

We are just trying to eliminate possible causes. If this works, then we have to consider what you might wish to make permanent by way of changes.

It has to be a configuration issue with this router!

sjdigital

31-07-2009, 11:33

Nope, disabling those didn't do the trick either. And I made the mistake of ringing VM tech support and got the usual reboot the modem answer! How to get through to someone who really is a tech person and not a call centre script reader?

Sephiroth

31-07-2009, 12:28

Apart from turning NAT off, maybe it's worth suggesting that you lend the Netgear over a weekend (if you don't need the VPN) to another nearby competent person with a similar set up while you use the Linksys. The second person can see what happens like reproducing the problem and fiddling with the settings.

sjdigital

31-07-2009, 13:33

Sephiroth

31-07-2009, 13:43

A sensible idea but it would require two things I can't be sure of finding - a nearby competent person, and one with a cable connection! I'll have one last try at VM and if no success then I may just pop the router in the drawer and continue to use my trusty Linksys.
If you're going to pop the Netgear into a drawer, send it to me and I'll mess around with it. If you're interested, I'll turn PM on to exchange details. I hate letting these things go!

sjdigital

31-07-2009, 20:16

Thanks for the offer but for the moment I'm going to pursue VM. I know it's not one of their routers but the problem is almost certainly with their network's DHCP server not liking something about this particular type of router and I'd like to try and find out what. And of course it may be specific to the network in Northern Ireland which is where I am.

Sephiroth

31-07-2009, 20:30

sjdigital

31-07-2009, 20:52

THanks. I've just posted a query on the Virgin Broadband Cable Support newsgroup so let's see what that comes up with. I'll report back when/if I have any news.

berkut

01-08-2009, 00:23

sjdigital,

Having read this entire thread can I ask a silly question as I have not seen this mentioned anywhere yet.

Have you at anytime changed the default MAC address on the WAN port?

Routers for the cable network normally have a clone function for the WAN MAC address as there tends to be more than 1 router with the same MAC. This allows you to copy the MAC from the network card of the PC you use to set up the router thus giving you a unique MAC on the network segment.

From what I am reading it sounds like there is a duplicate of the MAC that your router is presenting on the WAN port and this would cause the loss of connection as you describe.

Try changing the MAC address if you have not already done so.

sjdigital

01-08-2009, 09:55

Thanks for this suggestion. In fact I tried this at the suggestion of the Netgear Tech Support guy but it made no difference. And interestingly enough I posted a query last night on the Virgin Media Broadband Support newsgroup and the Virgin Tech Support guy there suggested the same thing. I did try it again but with no success and on thinking about it, it would probably be unlikely that three separate Netgear routers would all have MAC addresses that were dupicated by other devices on the VM network.

No, I'm afraid it's back to the drawing board on this one and in the meantime by trusty old Linksys WRT54G with dd-wrt firmware is doing the business.

Toto

01-08-2009, 10:32

Sephiroth

01-08-2009, 10:53

Back to one of my original thoughts - the settings on your router. We don't know the full set you're using so there is a blind spot here. Witht he router connected to the Cable Modem, id you go back to the default settings and in Ethernet ISP Settings check with Auto Detect that the settings are OK (DHCP Service Detected)? In the Advanced Options --> Use Default Address. For WAN Mode --> Classical Routing.

N3m3sis

06-08-2009, 17:40

Hi SJ
Sorry it has take so long to get back to this thread (pressure of work an all).
Please can you post the configuration screen of your cable modem and can you please tell me the model of it (Manufacturer and model no.) from what I have seen on this thread and the fact that the modem is giving the router a 192.168.100.x address
tells me the modems dhcp server is enabled and that function needs to be switched off. Once I can find out the make and model no, then we can look at turning of the pesky thing which really is a pain.

until the last spent shell falls

n3m3sis

sjdigital

06-08-2009, 21:52

Hi n3m3sis,
Great minds think alike, obviously, as only this evening I had another go at getting this resolved with the help of Netgear tech support. WE did get it working again and everything seems to point to some sort of conflict with the modem DHCP server as after doing a hard reset I still couldn't get an IP address until I rebooted the modem without rebooting the router. This did the trick (as it has done in the past) and seems to confirm an issue with the DHCP server in the modem. However the modem, an AMbit 256, doesn't give any access to settings - logging in to the modem web page (192.168.100.1) all you get is the status pages with no capacbilty of changing anything. I've asked VM broadband support (via the newsgroup suggested above) if there is another modem they could let me have and am waiting for their response.

Thanks again for your interest and support.

SJ

---------- Post added at 21:52 ---------- Previous post was at 21:41 ----------

Back to one of my original thoughts - the settings on your router. We don't know the full set you're using so there is a blind spot here. Witht he router connected to the Cable Modem, id you go back to the default settings and in Ethernet ISP Settings check with Auto Detect that the settings are OK (DHCP Service Detected)? In the Advanced Options --> Use Default Address. For WAN Mode --> Classical Routing.

Apologies for not acknowledging this before now. As you can see from my post above I got the router working again by using the Auto Detect button for the DHCP server. The first attempt wasn't successful, but rebooting the modem without rebooting the router and trying again did the trick. So the problem certainly seems to be related to the combination of that particular modem and router.

I'll report back when I hear if VM can give me an alterative one, or if the system crashes again!

Thanks again for your interest and support.

SJ