Listen issue

[thiagotalma]

Though it works the solution to use only one line in listen it is not the best solution.

It would be nice if the listen was set by default as follows:

server {
    listen 80;
    listen [::]:80 ipv6only=on;
}

Reference: https://chrisjean.com/fix-nginx-emerg-bind-to-80-failed-98-address-already-in-use/

A problem with using only one line is that the clients IPs are always converted to IPv6 (::ffff:192.168.0.2) and the systems that control access by IPv4 end up malfunctioning.

[drybjed]

First of all, I have an idea how to support both styles of configuration in the role and I'll try to implement it shortly to finish this issue once and for all.

But. I decided to design DebOps with both IPv4 and IPv6 enabled and present in mind. In 2015 there's no reason not to support IPv6 stack. If an application has a problem with interpreting IPv4-mapped IPv6 addresses, it needs to be fixed. For example, with Python there are modules which can be used to manipulate the IP addresses.

[thiagotalma]

The way I suggested both technologies work seamlessly.

The difference is that is honored the legacy of IPv4.

IPv6 is treated as IPv6
IPv4 is treated as IPv4

What is "wrong" is to force the IPv4 be treated as IPv6.

[drybjed]

I suppose that the real issue here is that nginx supports operation both as independent ports, as well as in "dual-stack" mode. Both styles of operation are valid, however they are mutually exclusive. I prefer the dual stack, so the debops.nginx role had support for it from the start. Now it will be possible to disable that, so I hope this will solve the issue.

As for which mode is enabled by default... I guess it's just personal taste. To set the separate ports instead of dual-stack, all you need to do now is set in group_vars/all/nginx.yml something like:

nginx_manage_ipv6only: False
nginx_listen_port: [ '80', '[::]:80' ]
nginx_listen_ssl_port: [ '443', '[::]:443' ]

This will make sure that all nginx servers will use separate listen ports for IPv4 and IPv6.