[ipv6hackers] IPv6 host scanning in IPv6

[Christiaan Ottow]

Hi Fernando,

See inline.

On Apr 21, 2012, at 17:58 , Fernando Gont wrote:

> Hi, Chris,
> 
> Thanks so much for your timely response! -- Please find my comments
> in-line...
> 
> On 04/21/2012 11:46 AM, Christiaan Ottow wrote:
> [....]
>> vic0:
>> flags=48843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_PRIVACY> mtu
>> 1500 lladdr 00:0c:29:50:3c:79 priority: 0 groups: egress media:
>> Ethernet autoselect status: active inet6
>> fe80::20c:29ff:fe50:3c79%vic0 prefixlen 64 scopeid 0x1 inet
>> 10.0.32.104 netmask 0xffffff00 broadcast 10.0.32.255 inet6
>> 2000:1337::8cab:b106:43b0:68f0 prefixlen 64 autoconf autoconfprivacy
>> pltime 14398 vltime 86398
> 
> This could be problematic, since these addresses are valid for just 24
> hours (vltime==86398). i.e., if you were used to e.g. days-long ssh
> sessions, this would break them.

Wouldn't vltime becoming zero break sockets on any platform, regardless of the presence of another global address?

> 
> That said, did you check whether OpenBSD configures new addresses once
> pltime becomes 0? If it doesn't, then after pltime seconds you'd have no
> "preferred" addresses. (After 24 hs or so, the system should have about
> 6 global addresses per interface -- assuming the same settings as above).

<snip>
# ifconfig vic0
vic0: flags=48843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_PRIVACY> mtu 1500
        lladdr 00:0c:29:50:3c:79
        priority: 0
        groups: egress
        media: Ethernet autoselect
        status: active
        inet6 fe80::20c:29ff:fe50:3c79%vic0 prefixlen 64 scopeid 0x1
        inet 192.168.170.134 netmask 0xffffff00 broadcast 192.168.170.255
        inet6 2000:1337::2c7d:ff20:4029:8590 prefixlen 64 autoconf autoconfprivacy pltime 14328 vltime 86328
# ifconfig vic0 inet6 2000:1337::2c7d:ff20:4029:8590 pltime 1800
# ifconfig vic0
vic0: flags=48843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_PRIVACY> mtu 1500
        lladdr 00:0c:29:50:3c:79
        priority: 0
        groups: egress
        media: Ethernet autoselect
        status: active
        inet6 fe80::20c:29ff:fe50:3c79%vic0 prefixlen 64 scopeid 0x1
        inet 192.168.170.134 netmask 0xffffff00 broadcast 192.168.170.255
        inet6 2000:1337::2c7d:ff20:4029:8590 prefixlen 64 pltime 1712 vltime infty
# ifconfig vic0 inet6 2000:1337::2c7d:ff20:4029:8590 pltime 60   
# ifconfig vic0                                                
vic0: flags=48843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_PRIVACY> mtu 1500
        lladdr 00:0c:29:50:3c:79
        priority: 0
        groups: egress
        media: Ethernet autoselect
        status: active
        inet6 fe80::20c:29ff:fe50:3c79%vic0 prefixlen 64 scopeid 0x1
        inet 192.168.170.134 netmask 0xffffff00 broadcast 192.168.170.255
        inet6 2000:1337::2c7d:ff20:4029:8590 prefixlen 64 deprecated pltime 0 vltime infty
</snip>

When a new router advertisement comes along, a new tempaddr is configured:

<snip>
# ifconfig vic0
vic0: flags=48843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_PRIVACY> mtu 1500
        lladdr 00:0c:29:50:3c:79
        priority: 0
        groups: egress
        media: Ethernet autoselect
        status: active
        inet6 fe80::20c:29ff:fe50:3c79%vic0 prefixlen 64 scopeid 0x1
        inet 192.168.170.134 netmask 0xffffff00 broadcast 192.168.170.255
        inet6 2000:1337::2c7d:ff20:4029:8590 prefixlen 64 deprecated pltime 0 vltime infty
        inet6 2000:1337::a8ed:ca9e:e408:3d08 prefixlen 64 autoconf autoconfprivacy pltime 14368 vltime 86368
</snip>

So, this setup would not break connections I suppose, but would leave garbage addresses. I've leave the system running for a while to see when vltime becomes infty, and how long deprecated addresses stay behind when new addresses have been acquired.

-- chris

> 
> Thanks!
> 
> Best regards,
> -- 
> Fernando Gont
> SI6 Networks
> e-mail: fgont at si6networks.com
> PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492
> 
> 
>