DEBUG HINTS - Check the source is issuing multicast packets with TTL high enough to reach the recipients. - Check the multicast packets are not being dropped due to fragmentation problems. - Three easy options to test IGMPv3 joins from the receiver host: 1) Configure pimd on the receiver host with "ip igmp join": interface eth0 ip pim ssm ip igmp join 239.1.1.1 1.1.1.1 2) Use test_igmpv3_join command-line utility (provided with qpimd): test_igmpv3_join eth0 239.1.1.1 1.1.1.1 3) User the Stig Venaas' ssmping utility: ssmping -I eth0 1.1.1.1 To see multicast responses with ssmping, you will need run on the host 1.1.1.1 either: a) Stig Venaas' ssmpingd command-line daemon OR b) qpimd built-in ssmpingd service: conf t ip ssmpingd 1.1.1.1 - Using nepim to generate multicast stream from 1.1.1.1 to 239.1.1.1: Notices: a) The host unicast address 1.1.1.1 must be reachable from the receiver. b) nepim tool requires the receiver must be started *before* the sender. First: Start a receiver for that stream by running: nepim -q -6 -j 1.1.1.1+239.1.1.1@eth0 (Remember of enabling both "ip pim ssm" and "ip igmp" under eth0.) Second: Start the sender at host 1.1.1.1. The following command generates a 100-kbps multicast stream for channel 1.1.1.1,239.1.1.1 with TTL 10 and 1000-byte payload per UDP packet (to avoid fragmentation): nepim -6 -M -b 1.1.1.1 -c 239.1.1.1 -T 10 -W 1000 -r 100k -a 1d SAMPLE DEBUG COMMANDS conf t int eth0 ip pim ssm test pim receive hello eth0 192.168.0.2 600 10 111 1000 3000 0 test pim receive join eth0 600 192.168.0.1 192.168.0.2 239.1.1.1 1.1.1.1 show ip pim join INTEROPERABILITY WITH CISCO ! Cisco IP Multicast command reference: ! ftp://ftpeng.cisco.com/ipmulticast/Multicast-Commands ! ip pim ssm default ! enable SSM mode for groups 232.0.0.0/8 ip multicast-routing ip pim state-refresh disable no ip pim dm-fallback ! interface FastEthernet0 ip pim sparse-mode ip igmp version 3 -x-