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Las Vegas, NV

[NV] SOHO Static IP

I recently changed over from a residential HSI account to a SOHO account for the static IP. I finally sat down and started to setup my static and ran into the issue of the modem (sb6120) still assigning a dynamic IP. I called in and we did a bunch of ARP cache wiping and MAC spoofing on both the router and hardwired to my centos box to try and get it to give me the static IP. We didn't have much luck so they have to do the whole dance of sending out a tech who will inevitably have to call in and have my static IP changed (guessing). So my question is... Has anyone seen this issue with the sb6120s constantly assigning a dynamic IP even when the NIC is set to all the correct static settings?


Johnston, RI
The IP is not set by the modem, the modem has nothing to do with it. On cable networks the modem is a dumb (transparent) bridge between your Ethernet/TCP-IP network and the MSO's DOCSIS network.

If you're receiving a DHCP lease from Cox's DHCP server than your device is requesting said lease.


Las Vegas, NV
Correct, I should have said request instead of assign the lease. I guess my question is why would my modem be requesting a dynamic lease instead of the static that is set on the NIC?


Las Vegas, NV
A static IP is meant to be assigned statically. DHCP (dynamic) requests will still get a dynamic IP address, but your static IP will work as well - you just have to configure it manually.

Cable Centric Vendor Biased
Atlanta, GA
reply to tmlv
If you're getting a DHCP IP, your modem has nothing to do with it. You need to SET your CPE to use the static IP. Your modem can't do anything to "set DHCP" on a NIC that is set to use a static IP.


Las Vegas, NV
The CPE IS set to static, we tried it on multiple machines. It's not the first time I've set up a static CPE. I have a tech coming out to follow up on this. Even when everything is set statically on the router/direct wired NIC I was still getting a dynamic address from cox. (Confirmed by T2 support) I will give more detailed results after this has been resolved.


Las Vegas, NV
So I called back again and got a great tech (Chris G.) who checked to make sure I was on the right node (I was). He checked the IP pool to make sure it was correct. He then checked some other IP's in that range and found out that the IP I was given was for a different node! He had them pull a new IP from the pool and assign it to my account. I updated my router to the new IP, rebooted the modem and presto! Life is good again. It's refreshing to have a support tech that thinks on their feet.