ssh_exchange_identification error

[Louis Hopcraft <lhopcraft_(_at_)_telus_(_dot_)_net>]

Hi all

I have this problem with ssh, I can ssh from box A to box B, but I can't
go from box B to box A, and I receive the following error.

ssh_exchange_identification: Connection closed by remote host

I can ssh from box B any other's that I have on my network, and I can do
the same with box A.  The only problem is connecting box B to box A.

Anyone have any ideas?