Here is the list of WorldShare ILL and Tipasa IP addresses:
132.174.100.123 (corresponds to mailhost-dsdc.oclc.org)
132.174.100.127 (corresponds to mailhost2-dsdc.oclc.org)
Here is a list of the ILLiad IP addresses:
206.107.42.254 (corresponds to mhostap01pwdu.illiad.oclc.org)
If you are working with Article Exchange:
132.174.11.84
You could also add the full range:
132.174.*.*