Internet is all about names and numbers.  Host names and IP addresses and service names and port numbers are two name/number pairs that are important for AlmostVPN user.

Known Services

Let us deal with service names first.  Essentially, the service name is just a human-friendly way to refer to a port number allocated for a particular service.  We have already mentioned a few of the more often used services in this manual(like: pop3, telnet, http, to name a few). A special organization, Internet Assigned Numbers Authority(IANA), is responsible for registering newly invented services to prevent them from "stepping on each other".  IANA is a good idea, but, for one reason or another, it does not know about every single service in the world (for example, they still have not heard about BitTorrent port 6881).  To make a long story short, it is very probable that at some point you will want to deal with a port number that does not have well-known name.  If it ever happens to you, you will have two choices:

1. Use the port number and do not worry about assigning a name to it;
2. Invent a special name for this port and use the Known Services Manager to map this name into the number.

You can open the Known Services Manager by clicking on the next to any service-related combo box ( Service on the AlmostVPN Connections Manager and From and To ports on the Tunnels Manager )
As you can see, this Manager knows about some of the more popular services "out of the box".  You can use the button to add new services and the button to delete existing services.  You can change the service name or number by typing in the appropriate table cells. Click the button when you have finished to close this dialog.

Known Servers

Another set of names and numbers, which is very important for AlmostVPN user, deals with the host name to IP address mapping. Every host has to have a somewhat unique IP address to make it possible to access this port over the net. The "somewhat" qualification comes from the fact that an IP address' uniqueness is mandatory only inside single subnet.  It is perfectly legal to have multiple identical IP addresses in multiple different subnets.  If you want to access a host from outside of a subnet it belongs to, then the "somewhat unique" usually is not good enough and you have to get an Internet unique IP address and register an Internet unique name for it (If you want to know more about this you can read about DNS and ICANN on wikipedia). The important point here is that quite often the host name to IP address mapping for hosts on private network is, well... private and unknown to the outside world.  As long as most of the time people  use AlmostVPN to access private networks, it is quite possible that the host names assigned to hosts on such networks  are "un-resolvable" (you can not use DNS to get the IP address for such a name).  There are many ways to deal with this problem. The AlmostVPN way is to use the Known Servers Manager. You can open the Known Servers Manager by clicking on the next to any server-related combo box ( Host Name on Accounts Manager, AlmostVPN Connections Manager, Drives Manager and Tunnels Manager )