[TriLUG] IPv6 equivalent to dhclient list

[Aaron Joyner]

Oh, you said you didn't want to do that...  Whoops...  :)  That is the
canonical way that I know of to get the list of ipv6 hosts.  Unless you
want to do the truly awful idea of running DHCP for v6 hosts to get a
leases file, it's probably what you're left with.

ip -6 neigh, under the hood, is asking the kernel directly over a raw
socket.  I didn't find any convenient interface to that data via
/proc/sys/net.  I think you're stuck calling ip from the CGI... but why is
that bad?

On Tue, Jan 6, 2015 at 9:00 PM, Aaron Joyner <aaron at joyner.ws> wrote:

> $ ip -6 neighbor
>
> On Tue, Jan 6, 2015 at 8:46 PM, Alan Porter <porter at trilug.org> wrote:
>
>>
>> My home router is a small Linux box, a 2008-era "Fit PC 1.0".
>> It runs a few basic services, including dnsmasq, a DNS/DHCP
>> server.  Dnsmasq is in charge of allocating IPv4 addresses
>> to all devices in the house.  For IPv6, I have radvd, which
>> advertises my home subnet and route info.
>>
>> I have a simple web CGI script that shows a web page with a
>> list of clients who are on the home network.  Basically, it
>> reads /var/lib/dnsmasq.leases and shows that info in a tidy
>> little grid.
>>
>> lease time   mac addr             ip addr        host name
>> 0:09:10      6c:40:08:a3:b9:2e    172.31.1.57    hedwig
>> 0:05:34      00:27:10:b7:79:90 172.31.1.56    xps
>> 0:07:41      00:13:ef:d5:27:f8    172.31.1.31    garagepi
>>
>> ...and so on.
>>
>> I'd like to add IPv6 hosts to that list, but I don't know how
>> to get that info from my router, or if it even knows.
>>
>> How would I find the IPv6 machines on my network?  Do they
>> leave some trail when they do their little dance with radvd?
>> Is there some IPv6 equivalent to the ARP table (is it ndp)?
>>
>> I hope I don't end up doing something crazy, like logging
>> IP addresses with an ip6tables rule, and using that somehow!
>> Or writing a script that monitors "ip -6 neighbor show" and
>> keeps a lookup table.  And I really hope I don't have to do
>> some stunt that requires me to find the host on IPv4 before
>> I can look him up on IPv6!
>>
>> Ideas?
>>
>>
>> Alan
>>
>>
>>
>>
>>
>>
>> --
>> This message was sent to: Aaron S. Joyner <aaron at joyner.ws>
>> To unsubscribe, send a blank message to trilug-leave at trilug.org from
>> that address.
>> TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug
>> Unsubscribe or edit options on the web  : http://www.trilug.org/mailman/
>> options/trilug/aaron%40joyner.ws
>> Welcome to TriLUG: http://trilug.org/welcome
>
>
>