I don't understand this

[valain]

Any ideas on what could cause zabbix_server to log this:

010686:20060303:164004 Parameter [tcp.ping] became supported by agent on host [valain.reseau.local]
010686:20060303:164011 Parameter [tcp.ping] is not supported by agent on host [valain.reseau.local] Old status [0]
010686:20060303:164011 Parameter [tcp.ping] became supported by agent on host [valain.reseau.local]

Now what: is it supported or not, and what makes Zabbix change opinion so fast? :)