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I am having some severe trouble with my PCWRT dual band router

This topic contains 16 replies, has 2 voices, and was last updated by  bjensen2 1 year, 6 months ago.

Viewing 15 posts - 1 through 15 (of 17 total)
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  • #3176

    bjensen2
    Participant

    I installed this router about a month ago. My network setup is a simple cable modem with the router performing NAT and serving the 802.11 network. I have one device connected via an ethernet cable, the rest are wireless. On average we have 6-8 devices active on the network at any time.

    At first all was well. I was getting great throughput and all the devices were working seamlessly. When I first installed the cable modem (about three months ago) against my ISP’s servers I was seeing 500mbps down and 60mbps up. Starting about two weeks ago I began to notice some minor issues. Sometimes devices would suffer brief interruptions in their connections. I work from home most days and my VPN connection began to drop spontaneously every few hours. At first I would reboot the PC, or if that didn’t resolve the issue power cycle the cable modem, then the router, and sometimes one or more of those restarts would seem to alleviate the issue. But the interrupted connections became more and more frequent, and lasted longer, and time it took to complete every operation involving the network began to lengthen. Today the wireless network reached the point of being unusable. I can no longer maintain a VPN connection for more than about 5 minutes, and the throughput has slowed to a crawl. Browsing the web is like working over a slow dial-up connection. No amount of power cycling of the cable modem or router has any impact.

    Interestingly, things do not get any better if I connect my PC to the router via an ethernet cable. I tried flashing the firmware on the router to the latest version, but that did not seem to help at all. And it’s not just one device, the issues are evident on all of them. All of the wireless devices work without issue on other wireless networks.

    So, late this morning I bypassed the router and connected my PC directly to my cable modem. Instantly, all the issues were gone. My VPN connection did not drop even once and the blazing speed I remembered from when I first deployed this cable modem was back. I didn’t even have to reboot the PC, it just worked. Eventually I had to put the router back into the system as I was getting complaints about being the exclusive user of the household internet, and as soon as I reintroduced the router the dropped connection / slowness problems resurfaced.

    I am not sure what to do next. I like the features on this router and don’t want to junk it – I spent $100 on it just five weeks ago! But I can’t use it in its present state. Do you have any suggestions for further troubleshooting or steps I can take to restore the performance of the router?

    #3177

    support
    Participant

    That is a really strange problem. Since you have the same problem with WiFi and Ethernet, the problem seems to stem from the WAN connection, i.e., the connection between the router and the modem. I would suggest:

    1. Turn off Access Control on the router (at the router level) and see if there’s any difference.
    2. Use a different Ethernet cable to connect the router to the modem
    3. If the above does not make a difference, and you have an Ethernet hub/switch or another router around, put it in between the pcWRT router and your modem. Does that make a difference?

    If the above options do not help, please send email to [email protected]. We’ll help you out.

    #3182

    bjensen2
    Participant

    I tried the troubleshooting steps you outlined.
    1. Turning off Access Control made no difference.
    2. I tried two other cat 5E patch cables and this made no difference.
    3. I dug up an old Linksys router and turned off DCHP on the LAN. I inserted this device in between the cable modem and the PCWRT router so that it functioned as a switch. This does seem to resolve the issue, although the speeds I saw topped out at about 96mpbs (not surprising – it’s a 100 base T switch).
    4. I borrowed a gigabit switch for testing and replaced the Linksys switch with the gigabit switch. The speeds are now as high as 260mbps when my PC is on the 5ghz wireless network and near the router.

    Do these results indicate an interframe gap issue or something of that nature? Is there any way to fix this problem short of buying a redundant switch to sit permanently between the PCWRT router and the cable modem?

    #3184

    support
    Participant

    @bjensen2 We should be able to send you a replacement. We are currently out of stock but will restock in the next couple of weeks. Please send an email to [email protected]. We’ll let you know when it’s available.

    #3219

    bjensen2
    Participant

    I had to return the gigabit switch. I found that the PCWRT router was still dropping connections every 30-60 minutes even with the additional device between it and the modem anyway. I can’t really wait to get this settled as I need to be able to work from home, so I bought a gigabit router and restructured my home network a bit.

    At present I have the gigabit router handling NAT off the cable modem. The gigabit router has only two devices connected to it. The first is the old Linksys device which I reconfigured as a wireless access point and it serves a wireless network that I use only for my work PC. The second is the PCWRT router providing a separate wireless network that is used by all non-work devices. I can hold a VPN connection all day this way, and other members of the household are more or less OK, although they’re still telling me that they get “kicked off” periodically.

    So – a couple of questions:

    1. If I obtain a replacement router from you, how will it differ from the one that I already have?
    2. Is there a way to configure the PCWRT router as a wireless access point, that is, as a bridge only that does not perform routing, just extends the LAN created by the gigabit router?

    Thanks!

    #3225

    support
    Participant
    1. We’re suspecting there might be some anomaly with the WAN port on your unit. Swapping it out with another unit might solve the problem. If not, then it’s a systematic problem, which is very unlikely (so far).
    2. The pcWRT router must behave as a router in order to have the filtering functionalities.
    #3321

    bjensen2
    Participant

    Sent an e-mail.

    If I am willing to lose filtering functionality for the purpose of testing – is it possible to configure the device as a wireless bridge?

    Would it be possible to see anything in the logs? I am comfortable with using the command line.

    Thanks!

    #3340

    support
    Participant
    #3394

    bjensen2
    Participant

    I received the replacement router, thank you. The only difference I can see is that it’s running a newer firmware, version 2.03 I think. I set it up in place of the temporary setup I’ve been using with the gigabit switch, that is, I just patched it directly to the cable modem as I’d originally tried back in November.

    For an hour or so things seemed fine. I was able to reconfigure my household printer and add devices to the new wireless network. But soon enough my work VPN connection began dropping every few minutes, and other devices began to experience losses of internet connectivity, operations timing out, etc. I cannot tell whether it is any better than the original router, but I don’t think it is. So, I put the switch back in the mix as I describe above in my Dec 20 post and once again, as soon as I connect to the network hosted by the old Linksys router all the problems vanish.

    So – what next? Should I try disabling DHCP? I presume that if I do that I can reverse the changes by executing
    /etc/init.d/dnsmasq enable && /etc/init.d/dnsmasq start
    ? Or is there something else I can try?

    #3395

    support
    Participant

    @bjensen2 Thanks for the additional info. What brand/model is your cable modem? What’s the ISP?

    • This reply was modified 1 year, 7 months ago by  support.
    #3397

    bjensen2
    Participant

    It’s an Arris T25, running on Comcast gigabit internet service.

    #3398

    support
    Participant

    Can you try cloning the MAC address off of the gigabit switch and set it as the MAC address for the pcWRT router WAN connection? I.e., Override MAC address on the Internet Settings page.

    #3466

    bjensen2
    Participant

    So I’ve been running with a cloned MAC address for about four days, and… so far it seems to have resolved the issue. The gigabit router and the old Netgear wireless access point have of course been removed from the network and powered down. The PCWRT router is handling the WAN connections and all the home devices.

    I am not sure, however, that the cloned MAC address has really “taken”. My PCWRT router shipped with an public-facing MAC address of XX:XX:XX:XX:XX:0F and a private-facing MAC address of XX:XX:XX:XX:XX:0E. In Settings -> Internet -> Override MAC Address I entered the MAC address off the Gigabit router YY:YY:YY:YY:YY:C1. However… on the Status page, under Internet MAC Address in the top left hand corner, the old XX:XX:XX:XX:XX:0F is still displaying. I would have expected this to match the YY:YY:YY:YY:YY:C1 address that I set in Settings->Internet. Anyhow, populating the “Override MAC Address” and saving that setting is what appears to have fixed the router.

    I have the following questions:

    1. Why would overriding the MAC address fix the issue? Is there something “bad” about the XX:XX:XX:XX:XX:0F address, or something “special” about the YY:YY:YY:YY:YY:C1 address? The gigabit router was just purchased off the shelf and the YY:YY:YY:YY:YY:C1 address was what it shipped with;

    2. Would it work just as well to set any other random address, as long as it was not XX:XX:XX:XX:XX:0F?

    Thanks!

    #3469

    support
    Participant

    @bjensen2 Glad it’s working for you now! People reported some wackiness with Arris cable modems. For example, this: https://community.netgear.com/t5/Nighthawk-Pro-Gaming-Routers/Fix-for-router-constantly-losing-connection-in-bridge-mode/td-p/1641529.

    The above is for an Arris router in bridge mode, to which a simple modem is similar.

    You are right the MAC address override did not take effect. We’ll look into that.

    As the above link also shows, there doesn’t seem to be a clear rule about what MAC address the Arris modem likes. Sometimes, the modem just doesn’t work well with the router. And the technique to fix it is more like hit-and-miss.

    #3470

    bjensen2
    Participant

    Arris supplies the majority of modems used on cable internet service in the USA. There are millions and millions of them deployed. A systematic problem with Arris modems seems highly unlikely. What’s described in that post sounds like something Spectrum has imposed on their subscribers. An ISP can modify the behavior of the modem pretty much at will. But I’m not on Spectrum, and I’ve had no issue with several devices connecting to the T25, including my PC and a couple of different routers. This problem only arises with the PCWRT. I have a more plausible idea about what I’m seeing.

    The issue I’m encountering will manifest if there are multiple devices with the same MAC address on the network. One thing that makes me suspect this might be the case with the PCWRT is that the burned-in address doesn’t match the sticker on the bottom of the router (it lists XX:XX:XX:XX:XX:0C). Another thing is that the first WRT router, which was manufactured at least three months prior, if not earlier, had a very similar MAC address. The difference between the old and new MAC addresses is only 36 in decimal. Presumably more than 36 routers were manufactured during those months. So the MAC addresses of these routers are not sequentially incremented, and if they were randomly distributed across the 16 million possibilities available, the odds of me receiving two routers with random addresses <= 36 bits apart are phenomenally long. So my hunch is that many PCWRT routers ship with the same MAC addresses – hundreds or maybe even thousands. In fact, the reuse of MAC addresses is pervasive enough that I’ve now had two of them that were not unique on the particular segment of Comcast’s network to which I am connecting. That is, some other frustrated Comcast/PCWRT customer was experiencing the same problems that I was. There’s a way to test this theory… and I did.

    I tried the “random MAC address” option in the internet settings. This seemed to work just as well as the cloned address (and I actually do think the cloned address took effect, it is just a bug in the UI that does not display it on the status page). The reason that a random address would work is pretty simple – the randomly selected address is one of the 16 million possibilities that doesn’t match any used on any PCWRT routers manufactured to date, or at least not any that have been put into service on my network segment.

    I don’t really want to go forward with a cloned MAC address as that could later lead to a problem if the gigabit router is put back into service. I think the randomized MAC address is a reasonable fix, although I’ve never needed to do this with any other piece of networking equipment.

    If you do not believe that duplicated MAC addresses are the source of my issue, please explain why the randomized MAC address option (which, by the way, does seem to display correctly on the status page) would resolve the problem.

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