AddressResolverOptions does not accept bare IPv6 DNS server addresses

[shblue21]

Version

4.x, 5.x

Context

AddressResolverOptions#setServers says each DNS server entry is the IP address of the DNS server, optionally followed by :port. The Vert.x guide also says the default DNS server port is 53 when no port is specified.

Based on that, I expected a bare IPv6 DNS server address such as Google Public DNS IPv6 to be accepted and use the default port.

Currently, resolver initialization fails for this value, apparently because the IPv6 colons are interpreted as part of the host/port syntax.

This is only about the bare IPv6/no-port case.

Steps to reproduce

Vertx.vertx(new VertxOptions()
  .setAddressResolverOptions(new AddressResolverOptions()
    .addServer("2001:4860:4860::8888"))); // Google Public DNS IPv6

Do you have a reproducer?

No response

[shblue21]

This looks like a small parser edge case.

I took a quick look at the parser. The awkward part is the existing last-colon behavior: 2001:db8::1:5353 is currently read as 2001:db8::1 + port 5353, so the fix probably needs to be narrow.

[vietj]

we have code in UriParser to parse IPV6 addresses (parseIPLiteral) that we should probably reuse, this code is well tested

[shblue21]

Thanks, I’ll try reusing UriParser in this path.