Since at least 2.2.1, the zabbix agent no longer returns EOF if it can't connect to a web server on a particular port.

Here are some test results between 2.0 and 2.2 agents

user@xxxx:~$ zabbix_get -s xxxx02 -k web.page.regexp[0.0.0.0,ieb/test?format=text,888,"hhh"]
EOF
user@xxxx:~$

Agent debug log xxxx02:
29488:20140521:141938.404 Requested [web.page.regexp[0.0.0.0,ieb/test?format=text,888,hhh]]
29488:20140521:141938.405 HTTP get error: cannot connect to [[0.0.0.0]:888]: [111] Connection refused
29488:20140521:141938.405 Sending back [EOF]

Version:
rpm -qa | grep zabbix
zabbix_agentd-2.0.4

-----------------------------------
user@xxxx:~$ zabbix_get -s yyyy02 -k web.page.regexp[0.0.0.0,ieb/test?format=text,888,"hhh"]

user@xxxx:~$

Agent debug log yyyy02:
9216:20140521:142336.174 Requested [web.page.regexp[0.0.0.0,ieb/test?format=text,888,hhh]]
9216:20140521:142336.174 HTTP get error: cannot connect to [[0.0.0.0]:888]: [111] Connection refused
9216:20140521:142336.175 Sending back []

Version:
rpm -qa | grep zabbix
zabbix_agentd-2.2.3