IP Address and DHCP/CMD

The M3SE requires a Internet Protocol (IP) address for all TCP or UDP communication such as FTP or Telnet. The address is configured in the Ethernet module using the DHCP/CMD utility: 

	DHCP [-Q] [-F] [-N]

If you have a Dynamic Host Configuration Protocol (DHCP) server available (usually your home router or your Internet Service Provider) simply typing DHCP will configure the M3SE and show you the results. This will also create a file called DHCP/CFG with all the information obtained from the server. The -Q (Quiet) switch will prevent displaying the results. The -F (Force) switch will, if DHCP negotiation fails, use the values from the existing DHCP/CFG file.

If you do not have a DHCP server or do not wish to use one, you can manually set the IP address, subnet mask, and gateway address in the [IPv4] section of DHCP/CFG. Then invoke DHCP/CMD with the -N (No server) switch. This will read the file and configure the Ethernet module.

Once you've successfully run DHCP/CMD, you can test that it's working properly by typing "PING <ip address>" in a Windows command prompt or Linux terminal window.

It is recommended that you set up your local router to use a static IP address for your M3SE. See your router's manual for instructions on doing so. A static address will allow you to give the M3SE a name that can be used from your PC instead of needing to know its currently-assigned IP address. Under Windows, you can edit the file: 

C:\WINDOWS\System32\drivers\etc\hosts
to look something like this: 
	127.0.0.1	localhost
	192.168.1.1	router
	#192.168.1.2	PC
	192.168.1.3	TRS-80
	192.168.1.5	printer

after which you can access the TRS-80 by name. The Linux version of the file is /etc/hosts. The same file can be used on your TRS-80; see here for more information.

Note that the IP address of my PC, the one with this hosts file, is commented out with the # character. Windows 7 (and probably some other OSes) get confused when they see their own IP address in the hosts file, possibly resulting in long startup times and failure of some services (most notably the Windows 7 FTP server.)

There are some DHCP options that can be modified in the NETWORK/CFG file: 

	[DHCP Client]
	Config File = "DHCP/CFG"
	Hostname = "TRS-80"
	Timeout = 2
	Max Retries = 1

The Hostname variable is reported to the server during DHCP negotiation.

Here's a sample DHCP/CFG file.

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