[syslog-ng] IPv6 Link local address use with syslog-ng

[Philip Bellino]

Bazsi,

On the Linux 2.6.22.9 Redhat 4.1.0-3 Fedora Core 6 from CDs at my
disposal, you can edit the "/etc/xinetd.d/telnet" file and change
"flags" from IPv4 to IPv6. Note: You will still have IPv4 connectivity.

telnet fe80::zzzz:zzzz:zzzz:zzzz%interface_name - interface_name on most
Linux is "eth0"

Ping6 has a "-I" switch:

Ping6 -Ieth0 fe80::zzzz:zzzz:zzzz:zzzz

Ssh -6 -l username fe80::zzzz:zzzz:zzzz:zzzz%eth0

On Freebsd, I believe that their telnet,ping6, and ssh client supports
IPv6 by default and uses the same syntax above.

On Windows XP, look for the output of the ipconfig /all command for the
"Ethernet Adaptor Local Area Connection" and look for its Link local
address. That address will have a "%x" after it, where x is its
interface number. XP has a telnet and ping6 client.  The syntax for
those are:

telnet fe80::zzzz:zzzz:zzzz:zzzz%x
ping6 fe80::zzzz:zzzz:zzzz:zzzz%x

Solaris 8 and greater have telnet and ping that support IPv6 built in.

telnet fe80::zzzz:zzzz:zzzz:zzzz
Somehow Solaris knows how to add the scope internally, so specifying the
interface is not needed.

Ping -A inet6 fe80::zzzz:zzzz:zzzz:zzzz
The -A option denotes the address family to use.

I hope this helps.
Phil

-----Original Message-----
From: syslog-ng-bounces at lists.balabit.hu
[mailto:syslog-ng-bounces at lists.balabit.hu] On Behalf Of Balazs
Scheidler
Sent: Tuesday, November 20, 2007 9:15 AM
To: Syslog-ng users' and developers' mailing list
Subject: Re: [syslog-ng] IPv6 Link local address use with syslog-ng


On Tue, 2007-11-20 at 08:41 -0500, Philip Bellino wrote:
> Bazsi,
> 
> Linux 2.6.x, Windows XP, Windows Vista, FreeBSD, Solaris 8 and up. All
> support IPv6 which of course supports Link Local addresses. 
> Execute the following commands to see the IPv6 configuration:
> Linux/FreeBSD - /sbin/ifconfig
> Windows - ipconfig /all
> Solaris - ifconfig -a

This is not what I had mind when I requested packages to support link
local addresses. Of course ifconfig does it, otherwise it would not be
possible to configure interfaces.

I meant something like a telnet client, how do you tell telnet to
connect to a link local address?

When I tried to do that I got an error:

telnet fe80::290:f5ff:fe28:b55e
Trying fe80::290:f5ff:fe28:b55e...
telnet: Unable to connect to remote host: Invalid argument

The reason I asked is to have a peek at the interface they provide for
configuring the scope id.

I've now tried using telnet/ssh/ping6, and neither could connect to a
link-local address. I don't see its use then, it should be used without
further configuration, but it turned out it is not possible.


> 
> Why the IPv6 gurus require the link local address to be scoped is
> still
> a mystery to me, but since it is, the rule is that the stack needs to
> know which interface to send the IPv6 packet out of, so "ip_ttl" does
> not apply here.
> Please note that the scope_id is not needed for Link Global IPv6
> addresses. 

The reason I mentioned ip_ttl() is, that when setting that to 1 means
that the given packet will never leave the network. I  originally
thought this was the reason to use link-local addresses in the first
place.


-- 
Bazsi

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