routing and netmasks

kriteknetworks · February 23, 2008, 02:18:20 PM

Hi folks, I have some strange behaviour on linux I cannot grok...all configured IPs can be reached from outside (confirmed via HE connectivity). Internally I can ping6 all configured IPs EXCEPT for the ones I've set on eth0 on the box that serves as the router/gw for IPv6.

The details on the router box from my rc.inet6:

ifconfig sit0 up
ifconfig sit0 inet6 tunnel ::209.51.161.14
ifconfig sit1 up
ifconfig sit1 inet6 add 2001:470:1f06:33c::2/64
route -A inet6 add ::/0 dev sit1
sysctl -w net.ipv6.conf.all.forwarding=1
ifconfig eth1 inet6 add 2001:470:1f07:33c::10/64

ifconfig eth0 inet6 add 2001:470:1f07:33c::1
ifconfig eth0 inet6 add 2001:470:1f07:33c::1000
ifconfig eth0 inet6 add 2001:470:1f07:33c::2
ifconfig eth0 inet6 add 2001:470:1f07:33c::3
ifconfig eth0 inet6 add 2001:470:1f07:33c::4
ifconfig eth0 inet6 add 2001:470:1f07:33c::5

From radvd.conf:

interface eth1
{
AdvSendAdvert on;
prefix 2001:470:1f07:33c::/64
{
AdvOnLink on;
AdvAutonomous on;
};
};

From route -A inet6:

Kernel IPv6 routing table
Destination Next Hop Flags Metric Ref Use Iface
::1/128 :: U 0 2 1 lo
::74.93.245.185/128 :: U 0 0 1 lo
::127.0.0.1/128 :: U 0 0 1 lo
::192.168.1.1/128 :: U 0 0 1 lo
::192.168.1.5/128 :: U 0 0 1 lo
::/96 :: U 256 0 0 sit0
2001:470:0:63::2/128 2001:470:0:63::2 UC 0 6 0 sit1
2001:470:1f06:33c::/128 :: U 0 0 2 lo
2001:470:1f06:33c::2/128 :: U 0 45 1 lo
2001:470:1f06:33c::/64 :: U 256 0 0 sit1
2001:470:1f07:33c::/128 :: U 0 0 2 lo
2001:470:1f07:33c::1/128 :: U 0 19 1 lo
2001:470:1f07:33c::2/128 :: U 0 1 1 lo
2001:470:1f07:33c::3/128 :: U 0 9 1 lo
2001:470:1f07:33c::4/128 :: U 0 12 1 lo
2001:470:1f07:33c::5/128 :: U 0 2 1 lo
2001:470:1f07:33c::10/128 :: U 0 11 1 lo
2001:470:1f07:33c::1000/128 :: U 0 5 1 lo
2001:470:1f07:33c:52::4/128 2001:470:1f07:33c:52::4 UC 0 87 0 eth1
2001:470:1f07:33c:207:e9ff:febf:1789/128 2001:470:1f07:33c:207:e9ff:febf:1789 UC 0 5 0 eth1
2001:470:1f07:33c::/64 :: U 256 0 0 eth1
2001:470:1f07:33c::/64 :: U 256 0 0 eth0
2001:7b8:3:3f:201:2ff:fef6:574e/128 2001:7b8:3:3f:201:2ff:fef6:574e UC 0 153 0 sit1
fe80::/128 :: U 0 0 2 lo
fe80::/128 :: U 0 0 2 lo
fe80::/128 :: U 0 0 2 lo
fe80::4a5d:f5b9/128 :: U 0 0 1 lo
fe80::c0a8:101/128 :: U 0 0 1 lo
fe80::c0a8:105/128 :: U 0 0 1 lo
fe80::206:29ff:fee2:6991/128 :: U 0 76 1 lo
fe80::240:5ff:fe60:4e7f/128 :: U 0 0 1 lo
fe80::/64 :: U 256 0 0 eth0
fe80::/64 :: U 256 0 0 eth1
fe80::/64 :: U 256 0 0 sit1
ff00::/8 :: U 256 0 0 eth0
ff00::/8 :: U 256 0 0 eth1
ff00::/8 :: U 256 0 0 sit1
::/0 :: U 1 0 0 sit1
::/0 :: U 256 0 0 eth0

I cannot hit the eth0 IPs from inside the lan, but they can be pinged externally. Also I cannot use the above listed IPs as souce addresses to hit anything else on the lan. I tried adding /64 to the eth0 IPs, but still no pings from lan.

A ping from a lan box (inet6 addr: 2001:470:1f07:33c:207:e9ff:febf:1789/64 Scope:Global):

ping6 -c3 2001:470:1f07:33c::1
PING 2001:470:1f07:33c::1(2001:470:1f07:33c::1) 56 data bytes
From 2001:470:1f07:33c:52::4 icmp_seq=1 Destination unreachable: Address unreachable
From 2001:470:1f07:33c:52::4 icmp_seq=2 Destination unreachable: Address unreachable
From 2001:470:1f07:33c:52::4 icmp_seq=3 Destination unreachable: Address unreachable

--- 2001:470:1f07:33c::1 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2008ms

A traceroute6 from inet6 addr: 2001:470:1f07:33c:207:e9ff:febf:1789/64 Scope:Global:

traceroute to 2001:470:1f07:33c::1 (2001:470:1f07:33c::1), 30 hops max, 40 byte packets
1 daw1.kritek.net (2001:470:1f07:33c:207:e9ff:febf:1789) 2998.741 ms !H 2998.738 ms !H 2998.728 ms !H

route -A inet6 from inet6 addr: 2001:470:1f07:33c:207:e9ff:febf:1789/64 Scope:Global:

Kernel IPv6 routing table
Destination Next Hop Flag Met Ref Use If
::1/128 :: Un 0 1 1 lo
2001:470:1f07:33c:207:e9ff:febf:1789/128 :: Un 0 1 696 lo
2001:470:1f07:33c::/64 :: UAe 256 0 20 eth0
fe80::207:e9ff:febf:1789/128 :: Un 0 1 30 lo
fe80::/64 :: U 256 0 0 eth0
ff00::/8 :: U 256 0 0 eth0
::/0 fe80::206:29ff:fee2:6991 UGDAe 1024 0 61 eth0
::/0 :: !n -1 1 2 lo

------------------------------------------------------------------------------------------------

While using other IPv6 tunnels I've used the same configuration and never had an issue internally, the only difference being /48 allocations, and using /64 internally. I'm at a loss to understand why all these IPs can be hit externally, but IPs on eth0 on the gw box cannot be hit internally.

If I missed any details please ask, I tried to be as detailed and specific as possible, and I apologize for the huge post.

kriteknetworks · February 23, 2008, 05:17:33 PM

Solved, seems I'd forgotten that the IPs I'd assigned on eth0 are part of the /64 I use for eth1 and the lan boxes, under /48s previously used, the IPs I'd previously assigned to eth0 were NOT part of the /64 I used internally for the lan. Total user error.

samh · February 26, 2008, 01:35:58 PM

Glad to see you got it solved. (Ive done very similar recently, though ive also bricked a WRT54G recently too so maybe you dont want to be in the same group as me :))

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