LAYERS parameter on WMS GetFeatureInfo

[Smith, Michael ERDC-CRREL-NH]

All,

Why is the LAYERS paremeter part of the WMS GetFeatureInfo request required?
I think from looking at the WMS spec that it is optional, although this is
based on just a quick look through the specs. Right now, ArcGIS WMS does not
send the LAYERS parameter and therefore can't query a Mapserver WMS map. Is
Mapserver being overly restrictive or ArcGIS not fully following the spec?

Mike Smith
GIS Specialist/Physical Scientist/Oracle Developer
Remote Sensing/GIS Center of Expertise
Army Engineer Research & Development Center 
Hanover, NH
(603) 646-4765
michael.smith at erdc.usace.army.mil