A network monitoring tool such as Wireshark (formerly known as Ethereal) is invaluable when debugging problems with the real network connections. It is a graphical traffic analyzer that can analyze most common network protocols. Wireshark is available from http://www.wireshark.com.
There are some pitfalls one might encounter when trying to connect a simulated network to a real one:
- Trying to access the simulation host
Accessing the simulation host from the simulated network, or the other way around, is only supported with port forwarding and host connection. It is difficult—sometimes impossible—to access the simulation host from the simulated network when setting up an Ethernet bridging connection.
- Simulated OS has no route
When using a NAPT connection and the operating system of the simulated machine does not have a correct route to the real network, the simulated machine will drop the packets or send them to the wrong address. To view the routing setup on the simulated machine, use the command
netstat -r on Linux or route print on Windows. Note that these commands should be executed on the simulated machines. The simulated OS should have a default route to the service node.
- Simics uses the wrong host network interface
On a host with multiple network interfaces installed, Simics will only use one of them for a real network connection. If the default selection is incorrect, use the interface argument of the connect command to select the desired network interface. See the previous section Selecting Host Ethernet Interface.