Reader: AT&T tells me Time Warner Cable is blocking his VoIP

Reader: AT&T tells me Time Warner Cable is blocking his VoIP

Summary: A reader and information technology professional in the New York area sent me an email this morning that raises the possibility that his high-speed Internet service provider Time Warner Cable may be blocking his AT&T CallVantage VoIP service.Not only does the reader wish to describe his issue, but he would like to hear from others who may be undergoing similar experiences.

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A reader and information technology professional in the New York area sent me an email this morning that raises the possibility that his high-speed Internet service provider Time Warner Cable time_warner_cable.gif may be blocking his AT&T CallVantage VoIP service.

Not only does the reader wish to describe his issue, but he would like to hear from others who may be undergoing similar experiences.  But first, here's this reader's account o what's been going on:

This past Thursday, TimeWarner did a big upgrade of their service in our area where the network (primarily cable but I'm assuming Internet as well) went down for 3-6 hours. When it came back up, my CallVantage service has stopped working.

After many many hours of talking to both ATT and Time Warner, resetting the TA device, rebooting etc. I still have no phone service. The TA device clearly works - it sees all fo the IP Address info from Time Warner and ATT can see the device on their network. However, I cannot get dial tone.

ATT says the problem is that TimeWarner is blocking certain UDP ports their app needs. They claim they see this problem with TimeWarner Cable frequently. At this point, I am convinced they are right. Have you heard of this yourself? Is this legal? I've had no phone service for 4 days. Suppose my business was out of my house?

Anyway, I'm trying to find out if others have seen this kind of behavior by TimeWarner and what there is to do about it.

Topics: Mobility, Browser, Networking, Telcos, Unified Comms, AT&T

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11 comments
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  • Not just TimeWarner

    While I never had an issue with my old SunRocket account, the move to a new service has been less than pain-free. I am using VOIP.com now, which I chose based on price and features. I've had a number of issues over the months I've had the service, and I've been told directly by support representatives that they've seen numerous issues with Comcast customers, which is also my Cable provider and ISP. I know Comcast blocks ports, such as port 25, and this behavior is part of the Comcast/Bitorrent investigation. I would imagine many ISPs use similar tactics to manage their networks, at the expense of interoperability with some services.
    jheine
  • RE: Reader: AT&T tells me Time Warner Cable is blocking his VoIP

    Time Warner Cable here. We're not aware of any technical reason that this customer's service suddenly stopped working. We are, however, happy to work with him or her to help troubleshoot. He or she should reach me and I will facilitate. alex.dudley@twcable.com.
    alex.dudley@...
    • Cover it up

      I know this is old, but found this when Googling the issue I found. As a network engineer and fellow IT girl, I say shame on you Alex Dudley and Time Warner Cable! It is our duty to give honest technical opinions, not cover up for billionaire corporations. That's Glenn Britt's and his greedbag corporate henchmen's job. Can you explain why TWC blocks port 5060 specifically? Can you explain why other apps using rtp work over TWC, but those ports mysteriously close when SIP rings? I even reproduced this without NAT. Use a VPN tunnel and both problems go away. Explain that, you liar! Granted, ATT should not be one to talk because they do the same trick with rtp over wireless, even though they leave port 5060 alone, unlike TWC. My Verizon Wireless business hotspot does not suffer either problem, using the same devices and configs. I had this issue with twc in the past year, when all my SIP accounts stopped working. Guess you guys had to do something to keep TWC digital phone so overpriced. I am on twc Albany. Sad we have to use tunnels and/or vpn to use internet services on your overpriced monopoly internet. Got something to say? I'll throw logs in yours and the public's face. Try me!!!
      SeleniaITgirl
  • RE: Reader: AT&T tells me Time Warner Cable is blocking his VoIP

    Actual blocking of VoIP services is illegal and if I was this customer would promptly file complaints against the organization (Time Warner) with the FCC. This goes above and beyond any reasonable network management and once served with a complaint by the FCC (and I have done this before, it DOES turn heads) miraculiously the VoIP service in question would start functioning properly.
    JT82
  • RE: Reader: AT

    Its the same case with my VOIP (Teleblend). It stopped working the same day Thurday Feb 28th and still no service. Teleblend says Time Warner Blocked the ports and i have to call them. I called 5 times and every time Time Warner tells me they dont block any ports.
    Iam screwed here with no service at home from past 3 weeks. And i've tried all the things and everything points out the port blockage from ISP i.e Time Warner/RoadRunner in ROchester, New York

    ~Kiran
    v_kiranpakash
    • TIME wanner blocking ports upstate NY

      MY customer is in the same area.
      spencer.timmons@...
  • RE: Reader: AT&T tells me Time Warner Cable is blocking his VoIP

    I work for i2telecom,and I have seen the same thing. Customers devices not registering with our server.Had Customer call Time wanner with test results proving his case , and they told him that if he was not having any issues with his internet connection they could not help, Time wanner sucks.
    spencer.timmons@...
  • RE: Reader: AT

    I am in Pomona CA 91767/909 and I haven't been able to use my At&T iPhone since this morning. It was spotty early and for the last few hours I can't use any AT&T/Edge services (We haven't upgraded to iPhone 3G). My wife can't use her iPhone either. Curiously, my Internet is through Cable from Time Warner which has been flakey for two days and once it became evening/afterwork time for locals, my cable IP has been down intermittently all evening. I thought it coincidence, but as I realized that ATT added Blackberry service today (Oct 27) and notice other connections in problem times between ATT/TimeWarner, I am wondering if there is a connection.
    rharder
    • no

      Has nothing to do with it. Mine and some others' voip services are not from AT&T and are still blocked. Try any service on port 5060 and you will see it's blocked. Try a service on other non standard ports and they will register, but the rtp ports will be open, then close. Sometimes before you hear a single ring. Looks like DPI is also in use. Time for users to encrypt traffic!!
      SeleniaITgirl
  • Wow

    <p>Thats a little messed up...of course with Time Warner nothing ever fails to amaze me...all of those copanies are so money oriented...Oh and to any who care I found my <a href="http://voipreview.org">VoIP provider</a> through <a href="http://www.thedigest.com">www.thedigest.com</a></p>
    alexb4499
  • RE: Reader: AT&T tells me Time Warner Cable is blocking his VoIP

    It seems to be good solution
    http://voipsipsdk.com/Download.aspx
    it.ragester