GALIL: check ethernet block port and address commands

The galil supports an IK command, IK1 is supposed to block some external ethernet port access that might be useful. It does state that IK0 is the default for 2000 series and IK1 is the default for 4000 series, so we should confirm this.

In addition 4000 series support a SM (subnet mask) command so we may be able to restrict IP address access that way. You need to choose a SM that when applied to the galil IP address includes the PC ip address, which makes it slightly less easy to use, but may still provide a bit of protection.