Hi All, I have been having a look at this issue: https://bugs.openjdk.java.net/browse/JDK-8207404 which was raised by Goetz Lindenmaier. When I ran the tests on my AIX system I got the same results as Goetz listed in the issue. Looking at the failure I noticed that it was failing on a setsockopt call in the native code in the PlainDatagramSocketImpl.c file which returned a EADDRNOTAVAIL (Can't assign requested address) Looking at my network configuration using "ifconfig -a", I noticed that my interface "en0" which the test was trying to use did not have an inet6 address configured (see below - some addresses have been obfuscated with x's). en0: flags=1e084863,14c0<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST,GROUPRT,64BIT,CHECKSUM_OFFLOAD(ACTIVE),LARGESEND,CHAIN> inet 9.20.xx.xx netmask 0xffffff00 broadcast 9.20.xx.xxx tcp_sendspace 262144 tcp_recvspace 262144 rfc1323 1 configuring the IPV6 on my AIX box I then had a inet6 address configured for en0 en0: flags=1e084863,14c0<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST,GROUPRT,64BIT,CHECKSUM_OFFLOAD(ACTIVE),LARGESEND,CHAIN> inet 9.20.xx.xx netmask 0xffffff00 broadcast 9.20.xx.xxx inet6 fe80::xxxx:xxxx:xxxx:xxxx/64 tcp_sendspace 262144 tcp_recvspace 262144 rfc1323 1 with this configured the MulticastSocket tests all passed. Should these tests work without having IPV6 configured on the interface? Goetz, do you have IPV6 configured on the machine you were running these tests on? Thanks Steve Groeger IBM Runtime Technologies Hursley, UK Tel: (44) 1962 816911 Mobex: 279990 Mobile: 07718 517 129 Fax (44) 1962 816800 Lotus Notes: Steve Groeger/UK/IBM Internet: groeges@uk.ibm.com Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU Unless stated otherwise above: IBM United Kingdom Limited - Registered in England and Wales with number 741598. Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU