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Re: [leshan-dev] LeshanClient and IP address changes
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Kai,
Thanks for the replies. Both replies were helpful.
Regards,
Kiran.
>
> Message: 1
> Date: Tue, 27 Oct 2015 11:35:16 +0000
> From: "Hudalla Kai (INST/ESY)" <Kai.Hudalla@xxxxxxxxxxxx>
> To: leshan developer discussions <leshan-dev@xxxxxxxxxxx>
> Subject: Re: [leshan-dev] LeshanClient and IP address changes
> Message-ID:
> <B73A9BCFC299B74F914B3E07F7495FE3C209A2@xxxxxxxxxxxxxxxxxxxxxxxx>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Kiran,
>
>> 1. Does users of Leshan project have to listen for IP changes and send
>> a register request again ?
>
> The LWM2M spec indicates, that a LWM2M server should assume that a client is
> reachable under the IP address used for sending its "Register" request.
> Thus, if the client's IP address changes, it should send an "Update
> Registration" request in order to provide the LWM2M server with its new IP
> address.
>
>> 2. If I am behind a router firewall ( outgoing allowed ) with static
>> IP, do I have to listen for network changes ( like router restart ) and
>> register again ( for hole punching in router ) ?
>
> I assume you are talking about a NAT firewall, i.e. the router has a single
> public IP address and translates between private (internal) IP addresses and
> this single public IP address.
> Most of such firewalls/routers will create a mapping entry in their NAT
> table when you send an outbound UDP packet to the LWM2M server, thus
> enabling outbound and inbound UDP traffic between your (internal) LWM2M
> client and the LWM2M server (external). This mapping entry will usually only
> exist for a limited time only if no data is exchanged (for UDP this is often
> not more than several minutes). Thus, in order to keep the mapping entry
> alive (and thus allow for inbound traffic originating from the LWM2M
> server), you should update the LWM2M registration every few minutes. The
> exact frequency of updates required to keep the mapping alive depends on
> your particular router/firewall though.
>
> Regards,
> Kai
