How can I use the DHCP Name feature of CoBos device servers such as the UDS1100, XPress-DR, XPort-04 and MatchPort b/g?

---

Here are some explanations of the three options for DHCP name. We will use example text from the UDS1100 User Guide, Part Number 900-417, Revision E August 2012. User Guides for other CoBos device servers have similar text.

On page 40 of the current UDS1100 User Guide (http://www.lantronix.com/pdf/UDS1100_UG.pdf) it says:

"Default DHCP Name: If you do not change the DHCP name, and you are using an IP of 0.0.0.0, then the DHCP name defaults to XX.XX.XX.XX (XXXXXX is the last 6 digits of the MAC address shown on the label on the bottom/side of the unit). For example, if the MAC address is 00-20-4A-12-34-56, then the default DHCP name is C123456."

There is a typo in the first sentence. It should say "...the DHCP name defaults to CXXXXXX (XXXXXX is the last 6 digits of the MAC address..."

In other words, if you do nothing and leave the IP address set to 0.0.0.0, the UDS1100 will supply the DHCP name Cxxxxxx to the DHCP server, where xxxxxx is the last 6 digits of the MAC address. The example, "...if the MAC address is 00-20-4A-12-34-56, then the default DHCP name is C123456." is correct.

The next paragraph says:

"Custom DHCP Name: You can create your own DHCP name. If you are using an IP address of 0.0.0.0, then the last option in Server configuration is Change DHCP device name. This option allows you to change the DHCP name to an alphanumeric name (LTX in our example).

Change DHCP device name (not set) ? (N) Y
Enter new DHCP device name : LTX"

I.e. if you type a 'Y' when asked if you want to change the DHCP name, you will be prompted for a new DHCP name. The example uses "LTX" as the DHCP name sent to the DHCP server, but you can type in anything you want, e.g. "Test_Lab", "Accounting", "Radiology" or any other string you want to use.

The last paragraph says:

"Numeric DHCP Name: You can change the DHCP name by specifying the last octet of the IP address. When you use this method, the DHCP name is LTXYY where YY is what you chose for the last octet of the IP address. If the IP address you specify is 0.0.0.12, then the DHCP name is LTX12. This method only works with 2 digit numbers (01-99)."

I.e. if you specify a two digit number for the last octet of the IP address, leaving the first three octets set to 0, then the DHCP name will be the name you provided with that number appended. I.e. if you specify IP address 0.0.0.43 and change the DHCP name to "Test_Lab" the name the UDS1100 sends to the DHCP server will be "Test_Lab43".

Note that this has no effect on the IP address assigned to the UDS1100 by the DHCP server, it is only a method to add a two-digit number to a DHCP name that you specified.

If the DHCP server is configured to work with a DDNS (Dynamic Domain Name Server) then the DHCP name supplied by the UDS1100 can also be used as a DNS host name on your network.

As of the "Updated" date at the top of this page there is a pending documentation change request to fix the typo and add some explanation to the User Guide.

---

[Originally Published On: 03/10/2011 09:43 AM]