Troubleshooting Mac TCP/IP connections can be tricky because there are so many elements involved. Here is a brief guide intended to help users make sure they've checked all the essential components. Listed below are the most common causes of TCP/IP connection failures.

Note: Throughout the instructions, certain terminology is used. It is important that this terminology is understood before reading the instructions:

Guest: Computer initiating the Timbuktu Pro session.
Host: Computer on the receiving end of the Timbuktu Pro session.

• Make sure TCP/IP incoming access is selected
  Open up Timbuktu Pro on the Host computer and go to Setup:Incoming Access. Make sure that TCP/IP incoming access is checked. If not, all inbound TCP/IP connections will be denied.

• Make sure you have your Trusted Visitors setup correctly
  Have you setup Timbuktu Pro to allow inbound users? If not, you may not be able to connect. Open up Timbuktu Pro on the Host system and go to Setup:Visitor Privileges. Hit the New button to setup a username and password to remotely login to this system. Make sure to check off the services that you wish to allow this account to use and click Save. Please keep in mind the username and password are case sensitive.

• Ping response time and packet loss
  What is a ping? A ping is a method to determine whether a specific IP address is accessible. It functions by sending a packet to the specified address, waits for a reply and records the time the roundtrip takes. Typically Timbuktu Pro works best under 200ms ping response time. Anytime the ping response time is higher than 200ms, Timbuktu Pro can time out or "give up" looking for the Host computer. If Timbuktu Pro does manage to make a connection, some of the packets can get loss because Timbuktu Pro gave up sending some of the packets to the Host because it took so long. To determine if you have a high ping response time, it is our suggestion that you download a free ping utility such as Mac Ping or OS X's Network Utility (located in Applications:Utilities) to determine your response time.

  If you do have a high response time, this is can be cause of several factors. The most common is network traffic. This can be traffic on your own private network or your Internet Service Provider's network. Often trying a different Dial-Up number or disconnecting your broadband modem and reconnecting could help the situation. Also, if you are connecting to a Host behind a router, often the router can cause some packets to be lost. This often is caused by older firmware on your router. Try updating your firmware and see if you can successfully connect afterwards.

  If you are not able to ping, chances are there can be a firewall preventing a connection. If that is the case, the ports that Timbuktu Pro use must be opened. Also, it can be the result of using an outdated IP address or an internal IP address instead of a WAN IP address. To verify if you are using the correct IP address, open up a browswer on the Host computer and go to the website wwww.whatismyipaddress.com or www.whatismyip.com.

• Personal firewalls
  Do you have a personal firewall (ie Norton) that is blocking inbound access to your system? If so, the ports that Timbuktu Pro uses must be open. If you are making a Mac to Mac connection, TCP port 407 must be opened. If you are making a connection to/from a Windows system, then UDP 407 and TCP 1417-1420 need to be opened on your firewall. Also, some personal firewalls ma also restrict connections to only allow connections from specified IP addresses.

• OS X (Jaguar) firewall
  Mac OS X.2 and higher now has its own built-in firewall. If you have this firewall started on the Host computer and not have the proper ports open for Timbuktu Pro, the connection will fail. To open up Timbuktu's ports, go to System Preferences:Sharing:Firewall. Click on the New button. From the pull-down menu, choose Timbuktu (407) and click OK. Once this is done, in the Firewall window, make sure Timbuktu (407) is checked. If you are establishing a connection from a Windows Guest, then you need to complete an additional step. Click the New button again. From the pull-down menu, choose Other. In the Port Number, Range or Series field, enter in 1417-1420. You can put whatever description you choose and click OK. Again, make sure the description you chose is checked in the Firewall window. This should now allow you to successfully connect.

• Router not configured properly or not configured at all
  If you have a router present there is a good chance you will need to make configuration changes to it in order to allow Timbuktu Pro to connect through, and to the proper machine on its Local Area Network (LAN). Your router may be assigning private IP addresses to your machines. These private IP addresses can only be accessed by other computers on the same LAN. In order for computers from outside of your routers network to make it into the proper machine, you will need to setup what is called port forwarding or port mapping on your router. To find specifics on where it may be located on your router, please check our router configuration guides for your routers make.

  http://www.netopia.com/support/howtodocs/router.html

  For routers not listed or for troubleshooting your router, please contact your router manufacturer directly. We do have generic router guides available for both the Mac and Windows operating systems. These guides will give you the necessary information that you will need before you contact your routers support department for specific instructions.

  Windows connecting to a Mac:
  http://www.netopia.com/support/software/how2docs/win/nat.html

  Mac to Mac:
  http://www.netopia.com/support/software/how2docs/mac/nat.html

• Using an internal IP address instead of a WAN IP address
  Verify the IP address that you are using to connect to the Host computer. If the IP address you are using a 192.168.xxx.xxx or a 10.xxx.xxx.xxx IP address, then this is the problem. These IP addresses are private IP addresses that are only accessible directly on the Local Area Network (LAN) in which that Host is connected to. If the Guest computer is not on the LAN, then that IP address cannot be used to connect over the Internet. You would need to make sure your router is first configured to allow inbound Timbuktu Pro traffic. Then you would need to connect to the Host using the router's WAN/public IP address.

  For more detailed TCP/IP Locator tips, please visit our Troubleshooting the IP Locator feature technote at the following URL: TPM_076.html

• ISP blocking ports
  Some ISP's block certain ports in order to keep users from creating their own virtual networks on their network or for security risks. It is our suggestion that you contact them directly to see if the Timbuktu Pro's ports are opened on their network.

  The ports that Timbuktu Pro uses are as follows:
  Mac <-> Mac connection use TCP 407
  Mac <-> PC connections use UDP 407 and TCP 1417-1420
  PC <-> PC connections use UDP 407 and TCP 1417-1420

• Same activation keys
  Make sure that both systems in question do not have the same activation key installed. This can be checked by opening up Timbuktu Pro and going to Setup:Activation Key. One license of Timbuktu Pro is required per system. With each license, you are given a unique activation key. If both systems have the same key, one system will need its key changed, since a connection between the same key are prohibited. This can be done highlighting the existing key, within the Setup:Activation Key window, and replacing it with an alternate key.

• Proxy Server
  Older versions of Timbuktu Pro for Mac will not work through a proxy server either inbound or outbound. However, Timbuktu Pro for Mac versions 5.2.x and higher, include a feature which does allow outbound connections through an HTTP proxy. This feature can only be used to connect through proxies that fit the following criteria:
  • It must be an HTTP Proxy.
  • It must support the CONNECT method. This is the same method used for secure HTTP (HTTPS) connections.
  • It must allow CONNECTing to Hosts (servers) who use TCP port 407. It is insufficient for it to support connections to secure HTTP servers who use TCP port 443, the HTTPS port.

  Users can enable this feature in the Proxy Server Preferences. The choices for the proxy server setup are as follows: None - This is the default and should be chosen if there is no proxy on the network

  HTTP Proxy from Internet Control Panel/Network Preferences - This should be chosen if a Proxy Server is specified in the Internet Control Panel (OS 8.6/9x)/Network Preferences (OS X). If a user name and password are required to connect to the Proxy Server, they should be entered here. If the system will also be connecting to users on the same network, (not outside the Proxy Server), then enter an IP address and subnet here.

  HTTP Proxy Specified Below - This is almost the same as above, except that this choice would be used when there is a Proxy Server on the network, but the Proxy Server is not in the Internet Config on the system, so it must be specified here.

  Server name or address - Enter the address of the Proxy Server, followed by a colon ':' and the port used by the Proxy.

  Internal Networks - This is used when your company does connect to the Internet through a proxy server, but you also connect to systems internally. Including this setting allows your system to connect to any IP address in the range specified, without going through the proxy server.

  It might look something like this:

  209.49.0.0 255.255.0.0 (note that there is only a space between the IP address and the subnet mask)

  When you set Timbuktu up to connect through an HTTP proxy, you are in essence saying: 'Contact x.x.x.x at port 'x' and talk HTTP to it.' The proxy acts as a tunnel to the other port, which in this case is TCP port 407.

  It's important to note that inbound connections through a proxy server of any kind are not supported. This feature is only available in Timbuktu Pro for Mac version 5.2.x and higher.  This proxy feature is only available on the Macintosh and not the Windows version of Timbuktu Pro.

• TCP/IP is not setup correctly
  There are a few things to take a look at. First, make sure you can connect to the Internet via a web browser (ie Internet Explorer, Netscape Navigator). If you can, the next thing to look at is your TCP/IP settings. You can find these in your TCP/IP control panel on OS 8.6-9x or your Network Preferences on OS X. If you are connecting over a LAN, make sure that the subnet mask listed is the same on all machines involved in the connection. Also make sure that the IP addresses contain the exact first 3 sets of numbers (ie 192.168.100.3 and 192.168.100.4). If your systems are connected through a router, make sure the exact same router IP address is listed. If you have a broadband Internet connection and none of these suggestions change the outcome of your connection, contact your Internet Service Provider to verify that your TCP/IP settings are setup according to their specifications.

• Hardware problems such as cables and ports on hubs/routers
  Typically if you have a hardware issue with the cables or ports on the hub/router you may experience other TCP/IP problems such as not being able to see the Internet, not able to get e-mail, or not able to do file sharing with other machines on your local network. If you have any of these problems, you more than likely will have problems with Timbuktu Pro also.

  A simple way to test if the cable is the cause of any of these problems is to switch the ethernet cable with another cable from a machine that is working properly. If that does not resolve the issue, switch the port on the hub or switch or router that the ethernet cable of the machine is question is plugged into.

• VPN connection not allowing traffic through our ports
  Please check with your Network Administrator to make sure the required Timbuktu Pro ports (Windows) [UDP 407 TCP 1417-1420] and (Mac to Mac) [TCP 407] are open to allow the traffic to funnel through. One way to confirm this would be to use some sort of port scanning utility (LanGuard, Sygate, PC Flank). You may also want to check with the router/VPN clients manufacturer to confirm that your configuration is set up correctly. Please keep in mind that once your VPN is configured correctly, Timbuktu Pro should display a IP address that is associated with the remote network. Also, you should be able to ping/trace route to other machines on the remote network as well. Also, Timbuktu Pro's Chat, Notify, and Intercom services all use dynamic ports. These ports may vary from 1023 or higher. Netopia recommends that you open up a range or ports (1023-1053) in order to allow these services to function properly.

  Note: Please keep in mind in order for NT Authentication to work, the following ports must be opened as well.

  TCP 139, UDP 138, UDP 137

• Cannot find Host using the IP Locator (e-mail address)
  If your connection is failing using Timbuktu Pro's IP Locator feature, there are several reasons why this connection can fail. For troubleshooting tips, please visit the following how-to-guide at: TPM_076.html