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New Member
Posts: 5
Registered: ‎01-02-2017

ER-X SFP & Netgear CM1000

After looking over the forum for a while, I didn't see a good explanation for a problem I ran into today.

 

Anyway, I bought a new cable modem to replace my Motorola SB6141 - a Netgear CM1000 docsis 3.1 capable.  Anyway, after 2 very frustrating rounds with Comcast, I reverted back to the Motorola. Basically, the CM1000 will not hand out an ip address to my ERX-SFP, whereas the Motorola does without issue. (provider ip addy, not local network ip).  

 

The only way the CM1000 works, is directly attaching my computer, but that too takes around 7 or 8 minutes, to get the Comcast ip, and be able to connect to the Internet. 

 

I called Netgear support (pretty much worthless), plus they hung up on me.  However, they mentioned that the ERX-SFP is compatible with the Netgear CM1000, so I am wondeirng if I should give the modem another chance, or send it back to Amazon. 

 

Thanks  

Member
Posts: 727
Registered: ‎09-24-2017
Kudos: 139
Solutions: 57

Re: ER-X SFP & Netgear CM1000

If you do a search for this general issue (i.e. Comcast or other cable ISPs and difficulty grabbing an IP), you will find several threads that discuss sequencing as the general solution. I have contributed to those threads and I *thought* I was giving good advice (and it did seem to help some people).

 

As it turns out, though, I ran into this problem yesterday (Comcast, SB6141, ER-X) and no matter what I did, I could not get an IP on my WAN interface. I tried restarting the modem over a dozen times with various times between, different sequencing and everything. Finally, out of desparation, I set the WAN tnterface to "No address" and saved it. Then I set it back to "Use DHCP" and saved again. And like magic, it worked!

 

Give that a shot and report back.

Emerging Member
Posts: 92
Registered: ‎10-29-2012
Kudos: 21

Re: ER-X SFP & Netgear CM1000

Have you tried looking at your modem to make sure it is online and has downloaded to current firmware form comcast servers?

 

https://kb.netgear.com/000036375/What-s-the-latest-firmware-version-of-my-NETGEAR-cable-modem-or-mod...

 

This document show you how to log into the modem.

 

https://www.netgear.com/support/product/CM1000#docs

 

There would be a issue with a system capatiblity with Comcast as something is not requesting the address. If your computer takes 7 mintues as they should get IP with in a min of coming online. Have you tried leaving the edge router on the modem for 15 min to see if it pulls a IP. 

 

I have a DSL connetion when i change the modem sometimes it will take a few hours to get a IP this is a know issues with the provider. I can call and have them reset my connection and it will fix the issue ( I know as I work for them so can do it myself but we are correting this). 

 

It is upto you on if you want to try trouble shooting this more. I know that there is still alot of issues with the 3.1 modems still but should be correted in the next year.

New Member
Posts: 5
Registered: ‎01-02-2017

Re: ER-X SFP & Netgear CM1000

Thanks for the info. I actullay tired several times disabling and re-enabling the WAN interface (mine is set to eth0).  I even tried moving the cable to eth1 and disabling re-enabling trying to get an address. I also toggled off "no address" and back to DHCP several times with no luck. Of course resetting the devices serval times and waiting didn't work either. 

 

Comcast support is pretty hard to work with as well - language barrier and accent. They did try hard, but we didn't have any luck.

 

I looked over the post in this thread after this one, and I will do a firmware check on the modem tongiht before attempting to call Comcast again. I think it's worth one more shot with this modem. Finally, I was thinking of backing up the ERX config and then doing a factory reset on it and restoring. It seems like there is no sense in doing so with something as simple as getting and ip address via dhcp from the provider.  

 

Thanks

New Member
Posts: 5
Registered: ‎01-02-2017

Re: ER-X SFP & Netgear CM1000

Thanks for the info.  I am going to check the firmware before calling Comcast again.  

 

Also, is there any reason some providers would take a longer than normal (few seconds or less) to provide a DHCP address?  It doesn't make sense to me that they would have extra layers of complexity when you go to a new Comcast approved model of modem. 

 

 

Established Member
Posts: 1,137
Registered: ‎07-07-2014
Kudos: 219
Solutions: 71

Re: ER-X SFP & Netgear CM1000

[ Edited ]

Just want to throw in my experience: I use a Netgear N600 CM500 modem with an Edgerouter and it works great.  My ISP is RCN however, and they are pretty great too Man Happy  No DHCP issues, or otherwise, to speak of.

 

I don't think the incompatibility would be with the modem, but rather with Comcast, but I cannot tell you for sure, only that I've had good experience with Netgear modems.

Regular Member
Posts: 365
Registered: ‎01-09-2017
Kudos: 50
Solutions: 10

Re: ER-X SFP & Netgear CM1000

I also have the cm500 and the erx on Comcast and it works. Hang in there.
New Member
Posts: 5
Registered: ‎01-02-2017

Re: ER-X SFP & Netgear CM1000

Sorry for the somewhat late response. I ended up factory resetting the ERX and then running the WAN to LAN2 wizard to get it going. The weird thing is, before I reset it, I was watching the dashboard, and the ip from Comcast would flash on/off the screen very fast at times (for the WAN/eth0 interface). Maybe the ERX was hanging onto something in the ARP table?  Anyway, it was strange, so hopefully this will help others. 

 

After getting things going I took the time to setup vlans/routing on my Edge switch 24 port, connected to my ERX. The switch has no console port so that made things a big interesting with setup. Anyway, I have 3 vlans 192.168.11.0/24 client  192.168.12.0/24 server & 192.168.99.0/24 mgmt, 3 AC Lite Ap's, and 1 AP Mesh. I set the ports up in general mode at first then changed to trunk ports wth native vlan 11, but I couldn't get things working, and had to move the native back to vlan 12.  My controller is on vlan 12, and I didn't restrict access to it. Maybe I am just missing something simple with this. 

 

Here is the port config going to one of the AP's. 

 

switchport mode trunk
switchport trunk native vlan 12
switchport trunk allowed vlan 11-12,99
vlan pvid 11
vlan participation include 11-12,99
vlan tagging 11
poe opmode passive24v

New Member
Posts: 5
Registered: ‎01-02-2017

Re: ER-X SFP & Netgear CM1000

Hello, should I put this last part of my question in a different thread?  I have reviewed the Ubiquity documentation, and think this is really something little missing with either the swtich port/trunk config, or the controller. Previous to factory resetting my router, I was simply using the Edge switch with no vlans and everything was working fine. 

 

Please let me know if more information is needed. 

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