[ipv6-wg] RIPE 80 IPv6 wg session Wilhelms DSL broke, some unanswered questions

Hi wg,

On 14.05.20 14:36, Wilhelm Boeddinghaus wrote:
> I they at least stay to this, there is hope. You can then enable IPv6 
> later without recoding the app.

I just want to through also 2 cents: Dragons will be everywhere!

   To be more precise; now "the developer" has to make sure HOW the 
resolving is handled. By no means I'm a programmer but as an 
sys-/net-admin I have encountered several situations where 
"applications" or software in general resolve i.e. a name only once, and 
just stays with the answer for the whole runtime.
Bad example: Defaults of JRE 7 to 9 IIRC / Or software written in java 
provides/sets defaults for the JRE used.

An other related aspect: the software or library makes this configurable 
but the user/programmer is not aware of it, or its implications. Again 
Java; in early documents this was even considered a security risk to 
re-resolve a name. (No comment on that part from my side...) Or doing 
regular resolve had a chance to perform internal (D)DoS. (No kidding!)

Also, the resolve can be implemented in so many ways and so many times 
many things just get ignored... like: honer the TTL; or what if the 
answer contains more then one entry, is v4 over v6 preferred? or the 
other way, ....


What I want to say: Sadly its not that simple to just uses names. Devs 
need guidance here, and explanation from people who know a fair bit of 
how dns works to get the application behave properly. Also dev and ops 
have to do proper testing of the functionality of course, too.

TL;DR; Sadly we could extent Wilhelms talk by even more "reasons" why 
adoption especially in enterprises is sometimes, lets call it, difficult.

BUT, thanks for you talk Wilhelm!

Best,
Bernd