Why do I have to reboot my Comcast router to access some web sites?

Posted on 2012-09-04
Last Modified: 2012-09-04
I'm seeing some really odd behavior on my office LAN recently.  I have Comcast business class service using an SMC 8014 modem/router. No speed problems, but I lose access to specific web sites and then have to reboot the router to get them back. Two web sites in particular I lost access to in the past few days: and No problem accessing numerous others; just one or two. Reboot the router, and they're back.

I hesitate to call Comcast about this without some background info because I suspect they wouldn't believe me. In fact, I probably would not believe a user if one called and told me the same story. I don't have a clue how a router would prevent access from a few specific sites like that. Enlighten me, someone. Thanks.
Question by:tcianflone
    LVL 21

    Expert Comment

    by:Larry Struckmeyer MVP
    What supplies the DNS settings to the users on the LAN?  Is there a Windows or other server, or is this an ad hoc bunch of computers using the router for DHCP and DNS?  If so, try using a different DNS provider, such as Google or Verizon, just to see if that fixes it.  Otherwise, put the Comcast thingy in bridge mode and get a router/firewall with a bigger cache that does not fill up and to to sleep.
    LVL 1

    Author Comment

    No domain here; just a couple of peer-to-peer clients connected to the Comcast router/switch. Default gateway, DNS server and DHCP server all handled by the Comcast router. Next time this happens, I will switch DNS provider and see if that works. Can you point me to an article that talks about router caches filling up and such? This is a new concept to me and need to learn more about it. Thanks.
    LVL 21

    Accepted Solution

    You might also ask Comcast for a newer better thingy or a firmware upgrade.  But ISP supplied routers/modems/thingies are famouss for brain farts.  

    Search on the following:
    isp modem arp chache

    enjoy... I got 78.5K hits.
    LVL 1

    Author Closing Comment

    Well, this is a total surprise to me. Had no idea that those devices had arp caches in them. Makes sense now. On another thread I read that Comcast offers a DOCSIS3 compliant modem/router now which is much superior to the SMC device I have. Gotta call and see if I can get them to put in one of those.

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