socket and DynDNS

[Stephan Schulz]

In article <48ff6b61$0$1605$9b622d9e at news.freenet.de>, Martin v. Löwis wrote:
>
>You should look at the TTL of the DNS record, and re-lookup when it
>expires.

Sure. I can do that. But it would be so much nicer if a lower level
would already take care of that (i.e. by caching the lookup for the
lease time and then renewing the info).

>There will be *no* kind of protection for UDP messages. When
>the machine loses its IP address, it will stop receiving your
>messages, even if they are already in transit. If the provider
>re-assigns the IP address to some other customer, that customer
>will receive the UDP messages instead.

Indeed. I'm aware of that. The data is not particularly critical, so a
short outage or some misdirected data is not much of an issue
(although I'd like to avoid sending random packets to some
unsuspecting victim, if only to not scare some poor virus scanner).

>If you want safety, you need to implement it in your application,
>e.g. by the receiver side sending heart beat messages, and the
>sender side resending everything that might have been lost since
>the last heart beat.

Right. We don't need that safety. Indeed, this is for an external
convenience feed. For the real application, we have a controlled
environment, and loosing the occasional packet is much less critical
than the overhead and delays of a safe protocol. But this is getting
off-topic.

Bye,

    Stephan

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