if exists(select 1 from sys.server_triggers where name = 'tr1') drop trigger tr1 on all server
go
create trigger tr1 on all server for logon as
begin
declare @x xml = EventData()
declare @address nvarchar(25) = @x.value('(EVENT_INSTANCE/ClientHost)[1]', 'nvarchar(25)')
if @address <> '192.168.0.1' rollback
else commit
end
go