RT-N66U with Motorola SB6121 LAN issues

[Jormungandr]

I just got a Motorola SB6121 as my old modem kicked the bucket. I was having issues getting it to work at all, wasn't getting any connectivity unless connected directly to the modem. I managed to get the WiFi working, but LAN does not work at all. I noticed an issue with the DHCP I believe. It's giving me an IP in the 169.x.x.x range for some reason, which is odd. Even if I manually assign an IP, I still get nothing. I can't even connect to the router on the LAN. I've been trying to get it to work for hours now and I have no idea what else to try. Any help would be appreciated.

ipconfig:

Wireless LAN adapter Wi-Fi:

   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Intel(R) Centrino(R) Wireless-N 2230
   Physical Address. . . . . . . . . : 60-36-DD-BB-C8-53
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2002:ae3b:a29e:1:540e:4a6c:24ea:39b4(Preferred) 
   Temporary IPv6 Address. . . . . . : 2002:ae3b:a29e:1:cf:cb98:9e2b:1e01(Preferred) 
   Link-local IPv6 Address . . . . . : fe80::540e:4a6c:24ea:39b4%4(Preferred) 
   IPv4 Address. . . . . . . . . . . : 192.168.1.213(Preferred) 
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : 19 March 2014 13:41:29
   Lease Expires . . . . . . . . . . : 20 March 2014 13:56:33
   Default Gateway . . . . . . . . . : fe80::12bf:48ff:fe53:7ec8%4
                                       192.168.1.1
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DHCPv6 IAID . . . . . . . . . . . : 325072605
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1A-66-41-B5-B8-CA-3A-D4-5B-37
   DNS Servers . . . . . . . . . . . : 2001:558:feed::2
                                       2001:558:feed::1
                                       8.8.8.8
                                       192.168.1.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Ethernet:

   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Qualcomm Atheros AR8151 PCI-E Gigabit Ethernet Controller (NDIS 6.30)
   Physical Address. . . . . . . . . : B8-CA-3A-D4-5B-37
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::5867:9c3:15e3:7461%3(Preferred) 
   Autoconfiguration IPv4 Address. . : 169.254.116.97(Preferred) 
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : 
   DHCPv6 IAID . . . . . . . . . . . : 263768634
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1A-66-41-B5-B8-CA-3A-D4-5B-37
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

 

[TonyH]

Hi,
Assuming nothing changed on your computer NIC setting, Turn off WiFi and just try with LAN hook up. Turn off modem, router. and after waiting for 5 mins. or so turn them back on
and then do an ipconfig /flushdns and ipconfig /renew. See what happens.

 

[Pericynthion]

Depending on who your ISP is, you may have to register / activate the new modem.

The 169.254 is a 'private' address that most DHCP clients adopt when they dont get a proper DHCP response (rather than being blank).

In my case (comcast) I had to call them to register the MAC address of the new modem, or they may give you a 'walled garden' to register itself. As an example heres the comcast process, but it may be similar for your ISP.


-Power off old modem
-Remove coax and Ethernet cables from old modem and install on new
-Power on new modem
-Allow the modem lights to stabilize
-Then open comcast.com in your web browser (any website will do, actually). If your system allows it, you'll be presented with instructions to register the new modem online.

If the online registration fails, or if you'd rather just let Customer Service take care of it, call 1-800-Comcast. You'll need to provide the brand, model, serial number, and HFC MAC address of the new modem.

 

[Jormungandr]

Yeah, I called to activate it as soon as I got it. I've tried restarting everything several times with no luck. WiFi works just fine, no issues at all, but LAN doesn't work at all.

 

[zainday4]

Ya....routers don't really matter unless it's a gateway router combo.....
But I know with comcast, if you get a new modem you need to contact them and let them register your mac id.....its usually written on the bottom sticker..
I would give that a shot....I've been through 4 modems since starting up along time ago and they have all needed contact with isp for mac id change....

PS...sorry you were posting while i was posting....so scratch my advice...lol...

 

[zainday4]

Look around on the modem and see if you see a little black button (reset) and hold it down for about 5-10 seconds.....shouldnt matter but worth a shot...

 

[zainday4]

Wireless LAN adapter Wi-Fi:
Subnet Mask . . . . . . . . . . . : 255.255.255.0

Ethernet adapter Ethernet:
Subnet Mask . . . . . . . . . . . : 255.255.0.0

Could that be it? I always have use 255.255.255.0 for all my stuff....
just something that caught my eye....worth looking into
(Just trying to help)

 

[Pericynthion]

Yeah, I called to activate it as soon as I got it. I've tried restarting everything several times with no luck. WiFi works just fine, no issues at all, but LAN doesn't work at all.

Ah ok - sorry I think I get it now. That ipconfig is from the end device (laptop etc)? So your laptop/PC isn't getting an IP address from the router over wifi, but that might be because its connected via the LAN as well at the same time.

It looks like the LAN interface is connected (it has a 192.168.1.213 address, and correctly has the 192.168.1.1 as the gateway).

With your laptop/PC connected directly to the router, can you access internet web sites ok?

It also looks like you have IPv6 enabled on this device and router so you'll have to make sure that (a) all the other devices support IPv6 and that (b) they have a similar 192.168.1.x IPv4 address to see them.

 

[Jormungandr]

Ah ok - sorry I think I get it now. That ipconfig is from the end device (laptop etc)? So your laptop/PC isn't getting an IP address from the router over wifi, but that might be because its connected via the LAN as well at the same time.

It looks like the LAN interface is connected (it has a 192.168.1.213 address, and correctly has the 192.168.1.1 as the gateway).

With your laptop/PC connected directly to the router, can you access internet web sites ok?

It also looks like you have IPv6 enabled on this device and router so you'll have to make sure that (a) all the other devices support IPv6 and that (b) they have a similar 192.168.1.x IPv4 address to see them.

It doesn't work if I have the WiFi off. I can get WiFi and if I'm plugged directly into the modem, it will work fine. But if I'm plugged into the router directly, it won't work. The modem is in IPv6 mode only, and I don't know how to change that, or even if I can. I know the router supports IPv6, and from what I've seen through some googling, it shouldn't be difficult to set up. I believe I did it correctly, as I have an IPv6 address when using the WiFi. I just don't understand why the LAN won't work at all, but the WiFi has no issues.

 

[RocketJSquirrel]

The modem is in IPv6 mode only, and I don't know how to change that, or even if I can.

I have the same modem. It turns out the modem's "IP mode" only refers to how the modem talks to Comcast. It is still providing you with IPv4.

 

[DavidEBSmith]

Have you tried something simple like using a different Ethernet cable or a different port on the router?

 

[Jormungandr]

Have you tried something simple like using a different Ethernet cable or a different port on the router?

Yep. Different cables, different ports, different computers, everything.

 

[KevTech]

It doesn't work if I have the WiFi off. I can get WiFi and if I'm plugged directly into the modem, it will work fine. But if I'm plugged into the router directly, it won't work.

Just wanted to make sure you are power cycling the modem when changing connection plugged into it. Most ISP allow a cable modem to attach to only one MAC at a time and you have to power cycle or reset the modem to release the MAC attached to the modem.

So if you had the modem with a direct connection to say a laptop and then plugged the modem into a router you would need to power cycle the modem to get the laptop MAC released and the router MAC attached to the modem.

 

[Jormungandr]

Just wanted to make sure you are power cycling the modem when changing connection plugged into it. Most ISP allow a cable modem to attach to only one MAC at a time and you have to power cycle or reset the modem to release the MAC attached to the modem.

So if you had the modem with a direct connection to say a laptop and then plugged the modem into a router you would need to power cycle the modem to get the laptop MAC released and the router MAC attached to the modem.

Yep, I noticed that it wouldn't work unless I power cycled it. Still no luck though.

On the bright side, the WiFi has been working without issue the last couple days.

 

[zainday4]

wonder if your input wan jack is working fine, but your other 4 aren't relaying....have you tried each one of the outbound ports...maybe ones faulty or maybe all of them....do you see leds blinking (next to the lan plug itself) on the ones that are plugged in, going to your cpu?