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Hi Eugene,

I found part of the answer. It looks like people often call this "plus addressing" and use this in exim.conf:

local_part_suffix = +*
local_part_suffix_optional

I took a look at exim4.conf and other .conf files but I often see "#--AUTOMATICALLY GENERATED - DO NO EDIT!". I tried to modify exim4.conf.template or update-exim4.conf.conf then run update-exim4.conf but it looks like my edit are not used.

Do you have an idea about how to make this work? :)
Thanks for the explanation, useful.
The weird thing about that is that I have another website with a similar server conf that doesn't generate the same issue. The port 80 is defined in the "Ports" tab and in the "Advanced" one.

server {
    listen 80;
    server_name www.example.com;
    return 301 http://example.com$request_uri;
}

server {
    listen *:80;
    server_name example.com;
(...)
Would it be correct to never include port 80 in any website "Ports" screen and specify ports only when using https, for example?
I can see some useful cases, even if it's not for reselling hosting. If you want to give a friend a FTP access to your server, you don't always want to give your own credentials.
Yes.
So, what can I do? Just ignore these warnings? I don't quite like that. ^^
It returns this:

nginx: [warn] conflicting server name "domain.com" on 0.0.0.0:80, ignored
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
Here you are:

#AUTOMATICALLY GENERATED - DO NO EDIT!

server {
	listen 80;
	server_name domain.com;
	return 301 https://domain.com$request_uri;
}

server {
    listen *:80;
listen *:443 ssl spdy;
    ssl_certificate /etc/ssl/domain_com.crt;
    ssl_certificate_key /etc/ssl/domain_com.key;
    server_name domain.com;

    access_log /var/log/nginx/domaincom.access.log;
    error_log /var/log/nginx/domaincom.error.log;

    root /srv/domain.com;
    index index.html index.htm index.php;

    location = / {
	rewrite ^ http://anotherdomain.com permanent;
}

    
    
    location ~ [^/]\.php(/|$) {
        
        
        
        fastcgi_index index.php;
        include fcgi.conf;
        fastcgi_pass unix:/var/run/php-fcgi-domaincom-php-fcgi-0.sock;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

    }

}
It gives an Nginx error, that's why I thought that there is a bug somewhere.

The code above gives this error: nginx: [warn] conflicting server name "example.comt" on 0.0.0.0:80, ignored
If I remove server { and } it becomes: nginx: [emerg] "listen" directive is not allowed here in /etc/nginx/conf.d/examplecom.conf:4