Skype ate my PC

Discussion in 'UK VOIP' started by Phil Thompson, Nov 24, 2006.

  1. Went into the office and found the PC chomping away at something,
    Netmeter showed 6 kbytes/s traffic both up and down.

    IPtools showed 14 screens of TCP connections to skype.exe processes,
    at least 400 active connections to a huge range of external IPs.

    Router firewall reported 2000 active streams (its limit) rebooted it
    with a new limit of 2500 and they were quickly filled up too.

    Email and web browsing very unreliable, lots of timeouts.

    Looked like dear old 192.168.0.35 had become part of Skype's
    infrastructure again. Couldn't even make a Skype call as it couldn't
    find a proxy ! bit off when it overloads the system to the point where
    it can't work itself.

    Such is life, Skype get paid millions by Ebay and I get to provide an
    infinitesimal part of their infrastructure :)

    Phil
     
    Phil Thompson, Nov 24, 2006
    #1
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  2. Phil Thompson

    The s-Bray Guest

    Skpe uses your PC as a supernode. Search Skype's website for supernode.
     
    The s-Bray, Nov 24, 2006
    #2
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  3. Phil Thompson

    Graham Guest

    Philip old boy, wasn't it you a week or so ago that described Skype
    as
     
    Graham, Nov 24, 2006
    #3
  4. you have to test these things out to understand how they work and
    their impact, then figure out how to solve any problems that arise.
    Otherwise when asked for advice I wouldn't have a clue.


    Phil
     
    Phil Thompson, Nov 24, 2006
    #4
  5. Phil Thompson

    Graham Guest

    Good answer.
    I have a spare expendable system for experiments like that.
    Its amazing what Win98 will pick up if left in the DMZ for
    an hour or two.
     
    Graham, Nov 24, 2006
    #5
  6. Phil Thompson

    Dave Guest

    The Skype Network Administrators guide claims that you shouldn't
    notice any decrease in performance when being used as a supernode.
    Clearly their claim just isn't true.

    "In addition, given the strict bandwidth limit placed on supernodes
    and relay hosts, Skype end users cannot tell the difference beween a
    given computer being used as a regular Skype node, supernode, or relay
    host because the capabilities required to support the additional
    functionality are transparent and have no noticable impact on a given
    computer's performance."

    See http://www.skype.com/security/guide-for-network-admins-30beta.pdf
    for full details.
     
    Dave, Nov 29, 2006
    #6
  7. Phil Thompson

    Paul W Guest

    I run Skype 24x7 and have done so for the last two years.

    I have never suffered any such problems so can only assume it must be your
    local configuration :)
     
    Paul W, Dec 17, 2006
    #7
  8. Phil Thompson

    Ivor Jones Guest

    There seems to be a problem with the configuration of your newsreader,
    it's top posting..!

    Ivor
     
    Ivor Jones, Dec 17, 2006
    #8
  9. Phil Thompson

    me Guest

    Wanker
     
    me, Dec 18, 2006
    #9
  10. Phil Thompson

    Ivor Jones Guest

    Ah, the old "I know I'm wrong so I'll swear" defence.

    It doesn't work.

    <plonk>

    Ivor
     
    Ivor Jones, Dec 18, 2006
    #10
  11. Phil Thompson

    dj Guest

    Wanker Squared
     
    dj, Dec 19, 2006
    #11
  12. If you can point me to the relevant configuration option in Skype I
    would be grateful. Something like "opt out of having 2500 unsolicited
    connections" perhaps.

    Phil
     
    Phil Thompson, Dec 20, 2006
    #12
  13. Phil Thompson

    JW Guest

    Don't run it as a service.
    Put your machine in standby when not in use.
    Use NAT.
     
    JW, Dec 20, 2006
    #13
  14. how ? I don't recall Skype presenting me with that option, where's the
    setting on the client ?
    it's always in use remotely.
    it is NATted, that's a myth.

    Phil
     
    Phil Thompson, Dec 22, 2006
    #14
  15. Recently, Phil Thompson popped out over the fence
    around uk.telecom.voip and said...
    |
    |>Don't run it as a service.
    |
    |how ? I don't recall Skype presenting me with that option, where's the
    |setting on the client ?
    |
    Don't run it... full stop.

    Or, should be installed to be fired up on request, not starting when the
    PC is started. Probably is the "Install for just me" and "Install for
    every user" option.

    If you tell me how does it start, maybe I can help you.

    Another option is to set up a proper QOS management, and choking the
    service inside your network for the packets marked with the Skype tag.

    NATting doesn't do, it's the client that advertises itself to the Skype
    network as a Supernode when it detects a (large) broadband connection.
    You are not "discovered" from outside, it's the client that does the
    trick: it gets your public IP and port and broadcasts it to the world.
    What annoys me is that this is done without the user knowledge or
    consent on bog standard installations. This is a blatant breach of the
    Computer Misuse Act, but nobody seems to care about it...

    Whatever.
     
    ßødincµs²°°°, Dec 22, 2006
    #15
  16. it's a test bed to see how Skype behaves in a practical installation.
    the "on request" bit wouldn't work for incoming calls, presence
    indication etc.
    I'll look and see, also see who is the owner of the process.

    My primary interest is to understand how a default Skype installation
    behaves and what the consequences might be.

    Phil
     
    Phil Thompson, Dec 22, 2006
    #16
  17. Phil Thompson

    JW Guest

    According to Skype itself: "a Skype client that is unable to
    receive inbound network connections (such as a user behind a
    NAT or firewall) will never become eligible to become a
    supernode nor will it ever be asked to relay a third party’s
    traffic"

    Are you saying this is wrong?
     
    JW, Dec 22, 2006
    #17
  18. yes.

    Unless there is some other modus operandi not covered by the above
    that involves data flow to and from the PC and 2500 simultaneous
    connections.

    At http://yarwell.blogspot.com/ you can see the IP address and ports
    of the machine concerned. I am not port forwarding 1174 to that PC as
    the above quote would suggest was necessary.

    Phil
     
    Phil Thompson, Dec 22, 2006
    #18
  19. Phil Thompson

    JW Guest

    Were those connections all outbound, then? If not, it's a
    puzzle how inbound connections could be established without
    router port forwarding or a public IP address forwarding to
    that PC. Maybe someone in the Skype user forums could
    explain it.

    Did you say the PC was providing remote access? Does this
    provide a route through the firewall?
     
    JW, Dec 23, 2006
    #19
  20. its trivial really, the Skype client behind the firewall can solicit
    the inbound connections. They aren't "cold calling" connections they
    are part of a P2P network with a client on my network.

    The Skype client could send a packet out saying reply to this on port
    xyz and the firewall would accept that as a reply associated with the
    outbound request.

    Type "netstat" at a windows command line and you'll see lots of
    inbound connections that are responses to things like web browsers.
    obviously, but not for Skype ports. Its running SNMP and a web server.

    Phil
     
    Phil Thompson, Dec 23, 2006
    #20
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