Semiconductor & Computer Engineering
There are two mode in which you can use IPv6 in mIRC:
- Local mode - Using /server -6
- Global mode - Using the option (alt + o > Connect > options > ports button > Enable IPv6 support and prioritize IPv6 over IPv4 connections)
Local mode
When you use /server -6, mIRC binds to an IPv6 adapter, this overrides the Global mode for that connection only.
This means you cannot use IPv4 on that connection.
In this mode, using /sockopen with an host that resolve to an IPv4 IP address will not work by default.
In Local mode, you can force ipv4 support using the -4 switches on /sockopen and /dns.
Regardless, if you want to use IPv6 while still having IPv4 support (and without having to enforce it with -4), you must use the Global mode, see below.
Global mode
Remember, this option can be enabled/disabled at alt + o > Connect > options > ports button > Enable IPv6 support and prioritize IPv6 over IPv4 connections.
In this mode, IPv6 has priority but IPv4 is not disabled.
This mode is recommended. Use /server -6 only if you want to disable IPv4 for anything happening from that connection by default.