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Michael2020's avatar

Microcells Won't Connect Through Cox Network

I have three Microcells in our home. They allow us to have a cell site in our home using the internet connection. Microcells are made by CISCO and they're pretty much "plug and play" units - you plug them in to the internet, and they bring your cells phone full bars, etc. 

These microcells have been here in our home for 4 years with very little maintenance - ATT replaces them if there is a problem. There has been no changes in configuration or hardware in our home in the past 2 years.

Yesterday they stopped working.

Our internet was the first suspect because what would affect all units at once? But our internet tests rock solid, no jitter, plenty of speed. 

We also thought well perhaps the Netgear CG3000DV2 router changed but we tested it and Cox says it is OK.

We spent hours working with ATT troubleshooting the units - restarting them and attempting to reload the software from the ATT servers but the units just cannot contact the ATT server.

So we looked into the ports they use. They use 123, 443, 500, and 4500. It appears from speaking to ATT that port 4500 is where they do the remote management and download of the software including updates. And we checked these ports on our router. All ports on the router are open.

So now we know that the problem is most likely port 4500 being blocked but not inside our house.

I have called Cox and explained the problem and asked for help. I know that Cox is more equipped to solve this problem than ATT because they are only able to help with devices - they will send me replacements for free but I know that won't fix my problem. I reviewed the ports that are blocked by Cox for "policy" - that means that they have a policy for instance of not allowing people to host a file server or web server at their home - they block those ports by policy.4500 is not one of the ports they block by policy.

So how can I work with Cox in a manner that would get them to help me find the problem?

Does anyone have any insight into how to solve this complex problem?

The problem definition is simple - Cox is blocking port 4500 somewhere and I need their help to find out where."

I have gone through a lot more troubleshooting and verification than I have listed here so just ask and I'll tell you if we've done it.

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  • Tecknowhelp's avatar
    Valued Contributor II

    Port 4500 is not blocked by Cox at the ISP level, as seen here. 

    Port 4500 is for IPsec, which is usually configured as a NAT passthrough, but it may not be enabled. See page 34-36 of manual and make sure "IPsec passthrough" is checked/enabled.

  • Techno - I appreciate the help....Yes, I had gone over the list of policy blocked ports with Cox earlier to make sure there was nothing blocked that they knew about. So my statement was more related to a non-policy block of the port.

    I would like to implement your suggestion but the manual you reference doesn't look anything like my router interface and I'm stumped about how to find the features you mention. Here's my interface as a screen shot.

    I tried to find the features you mention and can't find them. I know this manual says it for my modem but there must be something different? Maybe the software version - I know there might be a newer version - mine is V1.03.03.

  • Looks like that section on Content Blocking was related to V1.02. It appears to be gone now. Not sure what that means.

  • MarcJC's avatar
    New Contributor

    So I am not alone - I have a microcell that's been working for the past year with no issues then for whatever reason it stopped working sometime overnight Dec 2nd - 3rd. I have the black Cisco DPH154 unit from AT&T and now it just sits there with all lights green but the top Network light is flashing. I went through all the troubleshooting steps, even did a full deactivate, hard reset, re-activate with no success. Had AT&T troubleshoot (least useful thing ever attempted) then finally had AT&T send me a replacement. The replacement has the same issue.

     All the regular stuff, no changes to my local config, my network is stable. On COX in Phoenix. I tested UDP on 4500 and it's open.

      AT&T appears to be useless as does COX in coming up with anything thus far and neither really seems to have any motivation to try. 

  • MarcJC's avatar
    New Contributor

    This actually seems like part of a larger issue. Please check out the AT&T forums, they are trying to work out the issue.

  • Tecknowhelp's avatar
    Valued Contributor II

    I can only make suggestions based on what the manual says and unfortunately Cox and Netgear both make changes to firmware without updating documentation. Based on the forum posts though, it seems it isn't just Cox, with lots of reports coming from FIOS and Charter and mostly effecting CA. Looks like the issue has been escalated to ATT engineers but with no ETR.

  • It appears that ATT resolved the issue. They haven't made an official statement but all three of my microcells started working today and it appears to be a system-wide fix for ATT so as a guess, they either pushed out a bad firmware upload for microcells or they pushed a bad upgrade to their servers - something that hit all at the same time overnight and took down certain microcells on all ISPs all over the US. No one can explain why it didn't take down everyone - perhaps it had to do with versions that didn't upgrade or download. But as time went on, hundreds of people were checking in with the same issue everywhere.