[aprssig] rotate.aprs2.net

[Phillip Pacier]

Thanks for your note.  The rotate address has had 20+ addresses in it for
as long as it has been in use, and you are the first person to note a
problem with it.  After doing some research, I cannot find anything about
a limit to the number of addresses that DNS round robin will support - but
I could be wrong.  When I do an nslookup with my Windows machines, it will
only return 8 of the addresses in the list, but I do not see an error
message.

If your APRS software has the ability to put multiple servers in a list,
you really need to do that instead of relying on any of the rotate
addresses.  The limitations of DNS round robin are well documented on the
web, and can cause problems if a server in the list goes down.

We have been discussing setting up regional rotate addresses, which would
diminish the number of servers in each address.  Ideas were along the
lines of usa.aprs2.net, japan.aprs2.net, etc.  Again, the limitations of
round robin will still be present, and the phycial location of your server
to one in your region may not correspond to the IP distance.  I would
appreciate any comments on this subject.

If anyone knows of an actual hard limit in the number of addresses that
can be put into a single DNS round robin address, please let me know!

73
Phil - AD6NH
www.aprs2.net


Chris Kantarjiev
>
> I restarted CDRVLY tonight (a WRT54 running OpenWRT linux) and it started
> getting "unknown resolver error" when trying to do a DNS lookup
> on rotate.aprs2.net ... that was odd. I could look it up just
> fine from my laptop and a couple of other systems.
>
> I dug a little deeper, and was startled to see that
> there are now 29 addresses returned for this query!
>
> That's great, but ... I'll bet that the problem is a limit
> in some embedded resolver along the way, probably not expecting to see
> more than 8 or 16 addresses. It might well not be the WRT, but rather
> the DNS code on my DSL modem/NAT box (which I don't control).
>
> Am I the only one seeing this problem? Perhaps the Tier2 folks
> could scale this back a little? For now, I'm connecting to
> rotate.aprs.net, which works, but doesn't seem as friendly.
>
> 73 de chris K6DBG
>
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