I install zenoss rpm in cenost 5.7  in vmware.

run this discory command:

/opt/zenoss/bin/zendisc run --now --monitor localhost --deviceclass /Discovered --parallel 8 --job 123Eewre234342 --range 172.18.3.1-254

2012-02-16 04:49:02,465 INFO zen.ZenDisc: Connecting to localhost:8789

2012-02-16 04:49:07,796 INFO zen.ZenDisc: Connected to ZenHub

2012-02-16 04:49:49,211 INFO zen.ZenDisc: Found IP '172.18.3.45' on device 'localhost'; skipping discovery

2012-02-16 04:49:49,212 INFO zen.ZenDisc: Found IP '172.18.3.46' on device 'localhost'; skipping discovery

2012-02-16 04:49:49,212 INFO zen.ZenDisc: Found IP '172.18.3.33' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,214 INFO zen.ZenDisc: Found IP '172.18.3.2' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,215 INFO zen.ZenDisc: Found IP '172.18.3.10' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,215 INFO zen.ZenDisc: Found IP '172.18.3.22' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,216 INFO zen.ZenDisc: Found IP '172.18.3.54' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,736 INFO zen.ZenDisc: Found IP '172.18.3.52' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,736 INFO zen.ZenDisc: Found IP '172.18.3.58' on device 'localhost'; skipping discovery

2012-02-16 04:49:55,736 INFO zen.ZenDisc: Found IP '172.18.3.51' on device 'localhost'; skipping discovery

2012-02-16 04:50:01,887 INFO zen.ZenDisc: Found IP '172.18.3.62' on device 'localhost'; skipping discovery

2012-02-16 04:50:01,887 INFO zen.ZenDisc: Found IP '172.18.3.61' on device 'localhost'; skipping discovery

2012-02-16 04:50:01,888 INFO zen.ZenDisc: Found IP '172.18.3.91' on device 'localhost'; skipping discovery

I think maybe iptables wrong,stop iptables (iptabales -F)  ,but still this......