zabbix_sender doesn't seem to deal with "" hostnames properly anymore. When I try to send a data file with "" as hostname I get the following error:

zabbix_sender [2890]: Warning: [line 1] '-' encountered as 'Hostname', but no default hostname was specified

Instead zabbix_sender is supposed to use the Hostname value from the agent config file.

Also when I specify the hostname on the command line I no longer get the error but the hostname still is not replace and I see the following values on the proxy:

23208:20120905:001443.684 Trapper got [{
"request":"sender data",
"data":[

{ "host":"-", "key":"apache[ReadingRequest]", "value":"14", "clock":1346796883}

,

{ "host":"-", "key":"apache[Closingconnection]", "value":"1", "clock":1346796883}

,
...