Troubleshooting pcAnywhere TCP/IP connections

Depending on your situation, follow the general troubleshooting steps in the following sections:

Firewall software installed on the host or remote computer:

  • A firewall software installed on the host or remote computer can block the connection to the host computer. Make sure that you allow the connection to and from the pcAnywhere program in the firewall software. Also, make sure that the TCP/UDP ports 5631 and 5632 are not blocked by the firewall.

Limitations of some Internet service providers (ISPs)

  • Some Internet service providers (ISPs) limit certain functionality, and may not be capable of supporting a pcAnywhere connection. They specifically disallow the use of remote control software within their network, as this is deemed a security risk. For more help, contact your Internet service providers (ISPs) to confirm if this is the problem.

    If your ISP is blocking unused or certain TCP/IP ports for security reasons, you can configure pcAnywhere to use the ports which are allowed by your ISP. For more information, read: How to change the IP ports that pcAnywhere uses

Host behind a router

pcAnywhere and satellite communication links

  • pcAnywhere remote control sessions are not supported over satellite communication links using TCP/IP or any other network protocol. With TCP/IP over a satellite link, Ping times are in excess of 1800-3000 milliseconds. This is too slow for pcAnywhere to function effectively. Connections at these speeds are, at best, sporadic. File transfers may be possible, but remote control is unlikely.

pcAnywhere video cache

    The pcAnywhere host and remote work together to cache the host's screens. You can make sure that the difficulties are not caused by a cached screen by turning caching off at the remote.

  1. Start Symantec pcAnywhere.

  2. Click Edit > Preferences.

  3. On the Remote Operation tab, uncheck the option Use pcAnywhere cache file.

  4. Click Apply > OK.

Routers not passing UDP packets

    If your network connection passes through routers that do not allow UDP packets through can cause pcAnywhere connection problems. To correct this, a pcAnywhere registry key can be configured when one or more routers between the Host and Remote has disabled UDP packets.

  1. Click Start > Run.

  2. Type the following in the run dialog box and click OK:


  3. Go to the following registry key:


  4. Right-click the TCPIPConnectIfUnknown key, and then click Modify.

  5. Set the value to 1.

  6. Click OK.

    If this works, then one or more of the routers or firewalls is not allowing UDP or directed packets through. You can still use pcAnywhere; however, if the host is in use by another user, then you will appear to make a connection to the host but you will see a black screen. Once the connections works, set this value to 0 if the routers pass UDP packets.

Using Ping and Tracert

    You can use TCP/IP utility programs to see whether you have a good communication channel between the remote and host computers. It is crucial that neither the host nor the remote computers are running any programs that use TCP/IP. Once connected to the host, you can run the TCP/IP applications.

  1. Click Start > Run.

  2. For Ping, on the command prompt, type the following command and press Enter:

    ping host_IP_address

    Where host_IP_address is the IP address of the host computer.

    Ping sends 32 bytes of information to the host four times.

  3. For Tracert, type the following, and then press Enter:

    tracert host_IP_address

    Where host_IP_address is the IP address of the host computer.

    Tracert shows the amount of time and the route the packet travels between the host and remote computer.

    Together, these two utilities can provide very valuable information about the TCP/IP connection. To get a good picture of the network connection between the remote and host computers, you may need to run these utilities multiple times. You may see some of the following results:

    • Ping returns four "Request timed out" packets

      This indicates that there are TCP/IP communication problems between the remote and host. Check that you have the correct TCP/IP address for the host. Following are the private IP address ranges:

      • -

      • -

      • -

      If you are using the Internet, and the remote's or host's TCP/IP addresses are in the above ranges, then one or both of them are using private TCP/IP addresses. These addresses are not routable across the Internet. You need to find the public IP address of the host and remote computers or the Internet gateway through which they are connected.

    • Ping returns a few "Request timed out" packets or Tracert returns a few "*"s

      This indicates that packets are lost. If lost packets are combined with high Ping times, it can cause problems with pcAnywhere connections.

    • High Ping times

      Compare the Ping times with this list:

      • Less than 100ms - Excellent

      • 100-200ms - Average

      • 200-400ms - Okay, but can cause occasional pauses, occasional disconnects

      • 400-800ms - Poor, will experience significant pauses, some disconnects

      • More than 800ms - Very poor screen updates, partial screens, black screens, frequent disconnects

      If the Ping times are high, it can result in connection difficulties with pcAnywhere such as black screen, partial screen draws, slow screen draws and disconnections. High Ping times and lost packets can be caused by the Internet service provider (ISP). Contact the ISP for assistance. Tracert can help pinpoint where the traffic problems are. If Tracert shows high initial trace times and only a small increase with each hop, then the ISP is most likely the source of the problem. If the initial trace times are good, and get worse at a certain hop, then it could be the host's ISP, or a router in between.

    • Ping and Tracert indicate a good communication path

      If the communication path is good and you still experience problems with pcAnywhere connections, check if the host is behind a router. For more information read: Cannot connect to a pcAnywhere host through a router.


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DOKUMENTUMAZONOSÍTÓ: v60761726_EndUserProfile_en_us
Operációs rendszer: Windows 7, Windows Vista, Windows XP, Windows Me, Windows Server 2008, Windows Server 2003
Utolsó módosítás: 22/05/2013