This packet is used by the Secondary client to request a Hash search, this type of query is performed by the currently connected Primary host.

[0x1772][ Packet Data Length : 2 ][ Search ID/Counter : 4 ][ Minimum Line Type : 1 ][ 00 : 1 ][ FileType : 1 ][ 00 : 1 ][ Hash : 16 ]

The field marked "Search ID/Counter " is unique to each individual search and will be contained in all of the search results (177A) returned for this specific request.
The counter increments for each specific search, this includes repeat searches.