Hi, I guess that it is a problem. All the times i saw bad checksum in tcpdump it was a problems with packet delivery via that interface, it is ok, as checksum need to be correct.
There are some checksum changes in ipv6 since 5.4, so it may be some new bug you was discovered. I cant test neighbor discovery on my 5.5 right now, but its working good on my 5.4. Try to write to tech@ list. >From Bastien Durel <bast...@durel.org> >Subject IPv6 problem >Date Fri, 01 Aug 2014 16:31:41 +0200 > >Hello, > >I face a strange problem with my IPv6 connection. (one of them, actually) > >I got an OpenBSD router I use to connect to 2 ISPs and various internal >networks. > >One of my link cannot use IPv6 from some time (as it's my backup link, I >can't say exactly when it failed). This provider have native IPv6. > >here is the connected interface: >sis1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > lladdr 00:00:24:cf:42:ad > description: WAN2 > priority: 0 > groups: egress > media: Ethernet autoselect (100baseTX full-duplex) > status: active > inet 192.168.1.1 netmask 0xffffff00 broadcast 192.168.1.255 > inet6 fe80::200:24ff:fecf:42ad%sis1 prefixlen 64 scopeid 0x2 > inet6 2001:41d0:fc8d:f200::1 prefixlen 64 > >When I try to ping the "outside world", I can see the packet leaving via >sis1 (tcpdump -i sis1 -nvv -s 1500 ip6) > >15:58:41.703964 2001:41d0:fc8d:f200::1 > 2001:41d0:8:91a::1: icmp6: echo >request (id:65fd seq:9) [icmp6 cksum ok] (len 16, hlim 64) > >(the "outside world" recieves it, and awnser) >Then the provider's router sends a nsol to my router > >15:58:41.751487 fe80::5a98:35ff:fe1c:af06 > ff02::1:ff00:1: icmp6: >neighbor sol: who has 2001:41d0:fc8d:f200::1(src lladdr: >58:98:35:1c:af:06) [icmp6 cksum ok] (len 32, hlim 255) > >it responds > >15:58:41.751588 fe80::200:24ff:fecf:42ad > fe80::5a98:35ff:fe1c:af06: >icmp6: neighbor adv: tgt is 2001:41d0:fc8d:f200::1(RSO)(tgt lladdr: >00:00:24:cf:42:ad) [bad icmp6 cksum 8c3a!] (len 32, hlim 255) > >then nothing happens. > >I had the same problem when the ISP's modem is put in bridge mode, >except the router that sens the sollicitation is a CISCO ... > >Is there something I can have miss in my side ? I see there's a "bad >checksum", could this be a problem ? > > >Thanks, > >-- >Bastien Durel
