Subject: Does a Teredo client send keepalive packets to Teredo Relays to maintain a mapping in the NAT ...

From: "John Spence" <[email-masked]>
Date: Thu, 9 Feb 2006 13:23:04 -0800

I apologize if this is in the spec - I could not find it.  I see
the Teredo client sends keepalive packets to the Teredo Server to
maintain it's address.    Does the client send keepalives towards
active Relay's to maintain the mapping for active sessions?  Of
if a sessions through a Relay goes quiet for 2 or 3 minutes is
the session considered ended?

Thanks.
----------------------------------------------------
John Spence, CCSI, CCNA, CISSP
Native6, Inc.
IPv6 Training and Consulting
[email-masked]
----------------------------------------------------

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From: "Christian Huitema" <[email-masked]>
Date: Thu, 9 Feb 2006 13:59:20 -0800

> the session considered ended?

The client does not send keep-alive packets to the relay. Clients and
relays maintain a cache of their active peers, based on the traffic
exchanged with these peers. If a peer drops out of the cache, bubbles
will have to be exchanged through the server before sending the next
packet.

-- Christian Huitema

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From: Rémi Denis-Courmont <[email-masked]>
Date: Thu, 9 Feb 2006 23:14:06 +0100

> the session considered ended?

You have to considered such a session as ended. Relay maintain a list of 
recently contacted clients. If they receive traffic from a client they 
have not heard of for a long time, they'll ignore the packet.

Following the rule that you should be strict in what you send, and lax 
in what you accept, you should rather restart the "IPv6 direct 
connectivity check" through your Teredo server, when you have not 
contacted any given remote IPv6 peer for some time.

If you wish to avoid the implied delay, you should send higher-level 
keep alives, if specified at given level.

-- 
Rémi Denis-Courmont
Student-engineer at the Ecole Centrale Paris
http://www.simphalempin.com/home/infos/cv.shtml.en