Beko Pharm
Oh neat, #curl has a `-6` option to use only #IPv6. That is exactly what I need to update some dynamic DNS entry with my domain registrar regularly via their HTTP API - saves me the trouble to parse the current IP at all 😁
Apr 10 at 10:50amWeb
Show threadNamed Bird1d ago

@bekopharm Don't be fooled though, #curl can still initiate IPv4 connections even with the -6 option!

Because "::ffff:1.2.3.4" and "64:ff9b::C000:B00B" are valid #IPv6 addresses that represent the IPv4 interface. I found out the hard way when someone thought it would be funny to put that in their AAAA record... 😅

Show threadLitchralee_v61d ago
@namedbird @bekopharm I can see how the Legacy-mapped ::ffff/96 address would open a Legacy IP connection, but surely the NAT64 64:ff9b::/96 address would open an outbound v6 connection (although the NAT64 translator would then open a Legacy connection), right?
Show threadNamed Bird1d ago
@litchralee_v6 @bekopharm As far as i am aware, both would eventually end up with an IPv4 connection going over the internet. It may not matter for most use-cases, but if your goal of using the -6 argument is to enforce IPv6-only traffic, you should be aware of these exceptions.
Show threadBeko Pharm1d ago
@namedbird @litchralee_v6 all good. It's the dns lookup that matters here. If ipv6 isn't working it doesn't get updated but is of no use for me anyway. Thanks for the heads-up tho.