The 6to4 stf0 interface flapping in/out of tentative in FreeBSD 11.0-RELEASE-p8...

Viktor Dukhovni freebsd at dukhovni.org
Sun Mar 5 02:14:50 UTC 2017


In trying to set up a 6to4 node under 11.0-RELEASE-p8, and the stf0
interface is constantly flipping in and out of "tentative" state, at
seemingly 1 second intervals.  Is that to be expected?  Am I missing
some non-obvious configuration setting?

   $ ifconfig stf0; echo; for i in $(seq 10); do ifconfig stf0 | grep inet; sleep 1; done
   stf0: flags=1<UP> metric 0 mtu 1280
        inet6 2002:6c15:5974:1::1 prefixlen 16
        nd6 options=101<PERFORMNUD,IGNORELOOP>
        groups: stf

        inet6 2002:6c15:5974:1::1 prefixlen 16 tentative
        inet6 2002:6c15:5974:1::1 prefixlen 16
        inet6 2002:6c15:5974:1::1 prefixlen 16 tentative
        inet6 2002:6c15:5974:1::1 prefixlen 16
        inet6 2002:6c15:5974:1::1 prefixlen 16 tentative
        inet6 2002:6c15:5974:1::1 prefixlen 16
        inet6 2002:6c15:5974:1::1 prefixlen 16 tentative
        inet6 2002:6c15:5974:1::1 prefixlen 16
        inet6 2002:6c15:5974:1::1 prefixlen 16 tentative
        inet6 2002:6c15:5974:1::1 prefixlen 16

My configuration is (slightly trimmed):

   $ ifconfig igb0
   igb0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=6403bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,VLAN_HWTSO,RXCSUM_IPV6,TXCSUM_IPV6>
        inet 108.21.89.116 netmask 0xffffff00 broadcast 108.21.89.255 
        inet6 2002:6c15:5974::1 prefixlen 64 
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
        status: active

   $ netstat -6rn
   ...
   default                           2002:c058:6301::              UGS        stf0
   2002::/16                         link#4                        U          stf0
   2002:6c15:5974::/64               link#1                        U          igb0
   2002:6c15:5974::1                 link#1                        UHS         lo0
   2002:6c15:5974:1::1               link#4                        UHS         lo0

In /etc/rc.conf I have:

   stf_interface_ipv4addr="108.21.89.116"
   stf_interface_ipv6_slaid=1
   ifconfig_igb0_ipv6="inet6 2002:6c15:5974::1 prefixlen 64"
   ipv6_gateway_enable="YES"
   ipv6_defaultrouter="2002:c058:6301::"
   ipv6_network_interfaces="igb0"
   rtadvd_enable="YES"
   rtadvd_interfaces="igb0"

Other than a slightly higher than desired packet loss rate (perhaps to be
expected with 6to4 tunnels), this does not seem to impact connectivity:

$ ping6 -c 20 -n mx01.domeneshop.no
PING6(56=40+8+8 bytes) 2002:6c15:5974:1::1 --> 2a01:5b40:0:2201::1
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=0 hlim=55 time=105.615 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=1 hlim=55 time=104.798 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=2 hlim=55 time=105.384 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=3 hlim=55 time=104.726 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=4 hlim=55 time=105.361 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=5 hlim=55 time=104.387 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=6 hlim=55 time=104.730 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=7 hlim=55 time=104.712 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=8 hlim=55 time=104.951 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=9 hlim=55 time=104.697 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=10 hlim=55 time=104.718 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=11 hlim=55 time=104.511 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=12 hlim=55 time=105.174 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=13 hlim=55 time=104.760 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=14 hlim=55 time=105.056 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=15 hlim=55 time=104.860 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=16 hlim=55 time=104.716 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=17 hlim=55 time=104.669 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=18 hlim=55 time=105.137 ms
16 bytes from 2a01:5b40:0:2201::1, icmp_seq=19 hlim=55 time=105.043 ms

I mostly the 100% sucsess also with www.google.com, but now and then a
few pings are lost:

$ ping6 www.google.com
PING6(56=40+8+8 bytes) 2002:6c15:5974::1 --> 2607:f8b0:400d:c00::6a
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=0 hlim=57 time=16.488 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=1 hlim=57 time=16.332 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=2 hlim=57 time=16.621 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=3 hlim=57 time=16.645 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=4 hlim=57 time=17.336 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=5 hlim=57 time=15.978 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=6 hlim=57 time=17.073 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=7 hlim=57 time=52.323 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=8 hlim=57 time=35.891 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=9 hlim=57 time=38.653 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=10 hlim=57 time=45.235 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=11 hlim=57 time=25.149 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=12 hlim=57 time=16.357 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=14 hlim=57 time=16.719 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=16 hlim=57 time=17.122 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=17 hlim=57 time=16.963 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=18 hlim=57 time=16.130 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=19 hlim=57 time=23.763 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=20 hlim=57 time=16.295 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=21 hlim=57 time=18.302 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=22 hlim=57 time=16.994 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=23 hlim=57 time=18.312 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=24 hlim=57 time=16.419 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=25 hlim=57 time=17.241 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=26 hlim=57 time=17.931 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=27 hlim=57 time=17.478 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=28 hlim=57 time=17.514 ms
16 bytes from 2607:f8b0:400d:c00::6a, icmp_seq=29 hlim=57 time=17.684 ms
--- www.google.com ping6 statistics ---
31 packets transmitted, 28 packets received, 9.7% packet loss

Possibly relevant sysctl output:

$ sysctl -a | grep ip6
net.inet6.ip6.forwarding: 1
net.inet6.ip6.redirect: 1
net.inet6.ip6.hlim: 64
net.inet6.ip6.maxfragpackets: 1017650
net.inet6.ip6.accept_rtadv: 0
net.inet6.ip6.log_interval: 5
net.inet6.ip6.hdrnestlimit: 15
net.inet6.ip6.dad_count: 1
net.inet6.ip6.auto_flowlabel: 1
net.inet6.ip6.defmcasthlim: 1
net.inet6.ip6.gifhlim: 30
net.inet6.ip6.kame_version: FreeBSD
net.inet6.ip6.use_deprecated: 1
net.inet6.ip6.rr_prune: 5
net.inet6.ip6.v6only: 1
net.inet6.ip6.use_tempaddr: 0
net.inet6.ip6.temppltime: 86400
net.inet6.ip6.tempvltime: 604800
net.inet6.ip6.auto_linklocal: 1
net.inet6.ip6.prefer_tempaddr: 0
net.inet6.ip6.use_defaultzone: 0
net.inet6.ip6.maxfrags: 1017650
net.inet6.ip6.mcast_pmtu: 0
net.inet6.ip6.no_radr: 0
net.inet6.ip6.norbit_raif: 0
net.inet6.ip6.rfc6204w3: 0
net.inet6.ip6.deembed_scopeid: 1
net.inet6.ip6.dad_enhanced: 0
net.inet6.ip6.mcast.loop: 1
net.inet6.ip6.mcast.maxsocksrc: 128
net.inet6.ip6.mcast.maxgrpsrc: 512
security.jail.param.ip6.saddrsel: 0
security.jail.param.ip6.: 0

-- 
	Viktor.



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