To set up a column in Microsoft Excel to accept an IP address format only, you can use Data Validation. Here are the steps:

1. Select the column where you want to apply the validation.
2. Go to the Data tab in the ribbon and click on Data Validation.
3. In the Data Validation dialog box, select "Custom" from the "Allow" drop-down menu.
4. In the "Formula" field, enter the following formula:
   Formula:

   =AND(ISNUMBER(--SUBSTITUTE(A1,".","")),(LEN(A1)-LEN(SUBSTITUTE(A1,".","")))=3) 

5. Replace "A1" with the first cell of the selected column.
6. Click on the Error Alert tab and enter a message that will appear if the user enters an invalid IP address format, such as "Please enter a valid IP address format (e.g. 192.168.0.1)."
7. Click OK to close the dialog box.

Now, when a user tries to enter a value in the selected column that does not match the IP address format (e.g. 123.456.789), they will see an error message and will not be able to proceed until they enter a valid IP address format.