Network Configuration

In order for clients to correctly connect to each other, each client must have a single, globally unique name. To accomplish this in DGI, we use a combination of the hostname of the node and port the DGI instance listens on. It is critical that each DGI has only one name globally that all nodes refer to. This requires correct configuration on all machines.

Assigning A Hostname To A Computer

DGI loads the hostname automatically: there is no need to specify a hostname in freedm.cfg. The hostname DGI loads can be found by running hostname; here is an example from our testing system:

$ hostname

The hostname is specified in /etc/hostname as the only contents of that file. When you set the hostname you must restart the machine for it to take effect.

Each machine in the system must have a unique host name specified in /etc/hostname

You can confirm that the hostname has been loaded correctly by invoking ./PosixBroker -u (again, on raichu.freedm):

$ ./PosixBroker -u

Making Other Nodes Reachable

Each node must also know how to reach each other node by the name you assigned them in the /etc/hostname file. This is done using /etc/hosts. Be sure to take special care to ensure that each name in /etc/hosts is exactly as you specified in each of the /etc/hostname files.

Here is an example of a well done /etc/hosts file:

TS7800-4:~# cat /etc/hosts localhost MAMBA1 MAMBA2 MAMBA3 MAMBA4 MAMBA5 MAMBA6 TS7800-1 TS7800-2 TS7800-3 TS7800-4 TS7800-5 TS7800-6
  • Each line is of the form “ipaddress hostname”.
  • The first entry in the file should be “ localhost”
  • The machine should appear in its own hosts file.
  • Make sure that each machine you want to reach is defined in the hosts file.
  • Make sure the hostname for each machine is exactly how you specified it in that machines /etc/hostname

Restart the machine to make sure the changes are applied correctly.

Once the network has been configured, you can go on to Configuring The DGI