CG3000DCR pulling IP from 2nd NIC.

Running MS server 2003 with 2 NICs. I'll call them LocalCard and OutsideCard. We have a block of 5 statics from Comcast. The OutsideCard is manually configured with one of those and of course plugged into the Comcast router. The LocalCard is set for dhcp and NOT plugged into anything at this time. When going to the Comcast router config page and looking at connected computers, I see the ExternalCard with the correct static IP.

Once I plug in a patch cable from the LocalCard to our in-house local network and then 'Refresh' the Comcast 'Connected Computers' page, that static IP that it was seeing from the OutsideCard changes to the local IP that the LocalCard gets from our in-house DHCP server. This did not happen when we had a SMC8014, but it died and had to be replaced.

Is this a big coincidence or is it the new router?

Thanks,

-bob

Responses

Accepted Solution

BobH

New Member

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3 Messages

10 years ago

Well I thought I would wrap this thread up.

Turned out to be the 'two default gateways' causing the problem.

For what ever reason, when we had the old SMC running this did not cause a problem but once we hooked up the new Netgear it reared it's head.

We changed the local card from DHCP to a local static IP and removed the default gateway on that card. We left the static config on the Comcast card and the default gateway.

We added a few static routes to our server so it could find our corporate office and two other remote buildings.

Thanks,

-bob

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train_wreck

Gold Problem solver

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610 Messages

10 years ago

wow very strange. have you tried doing a packet trace on the interface connected to the modem, and then plugging in your internal interface? possibly an ARP issue, where the Windows server is erroneously ARPing the modem with the internal address? other than that, i'm guessing you have firewalled the server appropriately to not forward LAN traffic out the external interface?

and by chance, your internal subnet doesn't happen to have the same numbering as the Netgear's own internal LAN address pool? (typically 10.1.10.[10-199])

EDIT forgot to ask, do you lose connectivity when this happens? if not, it MAY just be a config webpage glitch.

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BobH

New Member

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3 Messages

10 years ago

Thanks Train for the reply, we have been too busy to spend much time on this issue.

Here are the answers I can give you at this time based on what we have done or know.

The External card is firewalled(have not made any changes to that since we were running the SMC8014).

Our internal subnet does not use the same numbering as the Netgear.

We do not lose connectivity on the local card(inside our building), but our other locations on our WAN does lose the ability to connect to the server.(They connect through the 'local' card).

Will try and do the packet trace this week.

Thanks again,

-bob

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Comcast_Jon

Administrator

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1.5K Messages

10 years ago

Hello BobH,

Thank you for the information, the community appreciate it!

Good to hear that your issue has been addressed.

If you have any other question or can assist the community, please post.
We look forward to your presence in the forum!

And Train_Wreck glad to have you on the community, thanks again!

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