Useful Redirects

HTTPS Redirect

server {
    listen 80 default_server;
    listen [::]:80 default_server;
    server_name example.com www.example.com;
    return 307 https://$host$request_uri;
}

A 301 redirect is also an alternative but if a POST is made to a 301, then many clients will resubmit the request as a GET - which almost always will fail serverside. A 307 mandates the same request type.

Redirect requests to another server

server { 
   server_name example.com; 
   return 301 $scheme://example.net$request_uri;
}

Mobile Site Redirection

Nginx configuration to detect request from mobile user-agent and redirect them to mobile site.

location / {

    #mobile site handling as per user agent
    set $mobile_rewrite do_not_perform;     // variable to store action. default set to not perform redirection to mobile site.

    if ($http_user_agent ~* "(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino") {
        set $mobile_rewrite perform;
    }

    if ($http_user_agent ~* "^(1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-)") {
        set $mobile_rewrite perform;
    }

    #google bot mobile handling
    if ($http_user_agent ~* "(googlebot-mobile)") {
        set $mobile_rewrite perform;
    }

    if ($mobile_rewrite = perform) {
        proxy_pass https://www.mobile-domain.com:$port;
    }
}

HTTP location on HTTPS server

HTTPS server with http location:

server {
    listen 443;
    root /var/www/
    location / {
       ...
    }
    location /http {
        rewrite ^ https://$host$request_uri? permanent;
    }
}

HTTP server redirects to HTTPS except one location:

server {
    root /var/www/
    location / {
        rewrite ^ https://$host$request_uri? permanent;
    }
    location /http {
       ...
    }
}

Disallow Requests Based on Host or Country Code

Use Nginx map to parse fields and reject requests.

# Allowed hosts
map $http_host $name {
    hostnames;

    default       no;

    example.com   yes;
    *.example.com yes;
    example.org   yes;
    *.example.org yes;
    .example.net  yes;
    wap.*         yes;
}

# Allowed countries
map $geoip_country_code $allowed_country {
    default no;
    country_code_1 yes;
    country_code_2 yes;
}

server {
    listen 80 default_server;
    listen [::]:80 default_server;

    # Disallow access based on hostname
    if ($name = no) {
        return 444;
    }

    # Disallow access based on GeoIP
    if ($allowed_country = no) {
        return 444;
    }
...