I have a server in Kimsufi (OVH) Ping on ipv6 causes an error: # ping6 -c 5 ya.ru PING6(56=40+8+8 bytes) 2001:41d0:e:XXX::1 --> 2a02:6b8::2:242 ping6: sendmsg: No buffer space available ping6: wrote ya.ru 16 chars, ret=-1 ping6: sendmsg: No buffer space available ping6: wrote ya.ru 16 chars, ret=-1 ping6: sendmsg: No buffer space available ping6: wrote ya.ru 16 chars, ret=-1 ping6: sendmsg: No buffer space available ping6: wrote ya.ru 16 chars, ret=-1 ping6: sendmsg: No buffer space available ping6: wrote ya.ru 16 chars, ret=-1 --- ya.ru ping6 statistics --- 5 packets transmitted, 0 packets received, 100.0% packet loss # uname -a FreeBSD tank1.storage.com 11.1-STABLE FreeBSD 11.1-STABLE #0 r322164: Mon Aug 7 15:33:19 UTC 2017 root@releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC amd64 cat /etc/rc.conf: ... ifconfig_em0="DHCP" ipv6_default_interface="em0" ifconfig_em0_ipv6="inet6 2001:41d0:e:XXX::1/128" ipv6_static_routes="ipv6gw" ipv6_route_ipv6gw="-host 2001:41d0:000e:03ff:ff:ff:ff:ff -iface em0" ipv6_defaultrouter="2001:41d0:000e:03ff:ff:ff:ff:ff" ipv6_activate_all_interfaces="YES" ... # kldstat Id Refs Address Size Name 1 16 0xffffffff80200000 1f78608 kernel 2 1 0xffffffff8217a000 31f830 zfs.ko 3 2 0xffffffff8249a000 cba0 opensolaris.ko 4 1 0xffffffff82621000 2357f ipfw.ko 5 1 0xffffffff82645000 9a67 if_bridge.ko 6 1 0xffffffff8264f000 5e60 bridgestp.ko # netstat -m 1024/2531/3555 mbufs in use (current/cache/total) 1023/1263/2286/250830 mbuf clusters in use (current/cache/total/max) 1023/1254 mbuf+clusters out of packet secondary zone in use (current/cache) 0/3/3/125415 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/37160 9k jumbo clusters in use (current/cache/total/max) 0/0/0/20902 16k jumbo clusters in use (current/cache/total/max) 2302K/3170K/5472K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for mbufs delayed (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters delayed (4k/9k/16k) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0 sendfile syscalls 0 sendfile syscalls completed without I/O request 0 requests for I/O initiated by sendfile 0 pages read by sendfile as part of a request 0 pages were valid at time of a sendfile request 0 pages were requested for read ahead by applications 0 pages were read ahead by sendfile 0 times sendfile encountered an already busy page 0 requests for sfbufs denied 0 requests for sfbufs delayed # ifconfig em0 em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500 options=4219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC,VLAN_HWTSO> ether 00:22:4d:ad:ff:dc hwaddr 00:22:4d:ad:ff:dc inet6 2001:41d0:e:XXX::1 prefixlen 128 inet6 fe80::222:4dff:fead:ffdc%em0 prefixlen 64 scopeid 0x1 inet 5.196.YY.ZZ netmask 0xffffff00 broadcast 5.196.YY.255 nd6 options=8021<PERFORMNUD,AUTO_LINKLOCAL,DEFAULTIF> media: Ethernet autoselect (100baseTX <full-duplex>) status: active After the command "ifconfig em0 inet6 accept_rtadv 2001:41d0:e:XXX::1/128", connectivity appears on Ipv6 and ping starts working.
ENOBUFS usually means that ND layer can not resolve L2 address. And this is because you incorrectly configured your IPv6.
(In reply to Andrey V. Elsukov from comment #1) Read the description of the bug again. I described how I managed to get the ipv6 to work.
(In reply to Vladislav V. Prodan from comment #2) > Read the description of the bug again. > I described how I managed to get the ipv6 to work. It is wrong, and this is why it doesn't work. > ifconfig_em0_ipv6="inet6 2001:41d0:e:XXX::1/128" What is the reason of /128 prefix length? > ipv6_static_routes="ipv6gw" > ipv6_route_ipv6gw="-host 2001:41d0:000e:03ff:ff:ff:ff:ff -iface em0" This will not work on FreeBSD due to implementation specificity. > ipv6_defaultrouter="2001:41d0:000e:03ff:ff:ff:ff:ff" When the kernel is going to send IPv6 packet, it does L2 lookup to determine L2 address. ND6 code does lookup for destination address only when an address is considered as neighbor. When you have not configured the correct prefix, the ND6 has not any interfaces where the destination address can be considered as neighbor. In your case even the L2 address of default router can not be found.
(In reply to Andrey V. Elsukov from comment #3) >> Read the description of the bug again. >> I described how I managed to get the ipv6 to work. >It is wrong, and this is why it doesn't work. It's someone who did not quite correctly implement the IPv6 implementation in FreeBSD. I can give a working example for Debian, there is the same crutch in the destination route for the default router. >> ifconfig_em0_ipv6="inet6 2001:41d0:e:XXX::1/128" >What is the reason of /128 prefix length? So decided marketers in the OVH. I already pointed out to them that there are a number of vulnerabilities related to the substitution of IPv6 addresses. Personally, I only need one ipv6 address. >> ipv6_static_routes="ipv6gw" >> ipv6_route_ipv6gw="-host 2001:41d0:000e:03ff:ff:ff:ff:ff -iface em0" >This will not work on FreeBSD due to implementation specificity. Why not? It works the same. # netstat -rn6 Routing tables Internet6: Destination Gateway Flags Netif Expire ::/96 ::1 UGRS lo0 default fe80::12bd:18ff:fee5:ff80%em0 UG em0 ::1 link#2 UH lo0 ::ffff:0.0.0.0/96 ::1 UGRS lo0 2001:41d0:e:XXX::/56 link#1 U em0 2001:41d0:e:XXX::1 link#1 UHS lo0 ... 2001:41d0:e:3ff:ff:ff:ff:ff 00:22:4d:ad:ff:dc UHS em0 ... fe80::/10 ::1 UGRS lo0 fe80::%em0/64 link#1 U em0 fe80::222:4dff:fead:ffdc%em0 link#1 UHS lo0 fe80::%lo0/64 link#2 U lo0 fe80::1%lo0 link#2 UHS lo0 ff02::/16 ::1 UGRS lo0 >When the kernel is going to send IPv6 packet, it does L2 lookup to determine L2 address. ND6 code does lookup for destination address only when an address is considered as neighbor. When you have not configured the correct prefix, the ND6 has not any interfaces where the destination address can be considered as neighbor. In your case even the L2 address of default router can not be found. Honestly, I do not care how ND6 is implemented in FreeBSD. I have issued a static IPv6 address with a given mask. I have an IPv6 router address by default. So what if he's not in the L2 segment? The network interface, where this Ipv6 is located, I know. Next, with these packages, the switches and routers of the hoster will be sorted out. I have a typical network scheme for many hosters dedicated servers. I have a test machine with which I can work for a while to correct this abnormal behavior. If you have the time and the desire to eliminate this, in personal correspondence I will provide access to the server.