According the the documentation for the ipv6 network attribute https://libvirt.org/formatnetwork.html "When set to yes, the optional parameter ipv6 enables a network definition with no IPv6 gateway addresses specified to have guest-to-guest communications." But this is not the current behavior, the ipv6 attribute is ignored and the resulting /proc/sys/net/ipv6/conf/<virbrX>/disable_ipv6 gets set to 1 even when ipv6="yes". This commit fixes that by checking for the ipv6 network attribute during bridge setup. Signed-off-by: Ryan C Goodfellow <rgoodfel(a)isi.edu&gt; --- src/network/bridge_driver.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index 4bbc4f5a6d..69022fbfbb 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -2221,7 +2221,8 @@ networkSetIPv6Sysctls(virNetworkObjPtr obj) virNetworkDefPtr def = virNetworkObjGetDef(obj); char *field = NULL; int ret = -1; - bool enableIPv6 = !!virNetworkDefGetIPByIndex(def, AF_INET6, 0); + bool enableIPv6 = !!virNetworkDefGetIPByIndex(def, AF_INET6, 0) | + def->ipv6nogw; /* set disable_ipv6 if there are no ipv6 addresses defined for the * network. But also unset it if there *are* ipv6 addresses, as we -- 2.17.1