Certbot Successful, but site cannot be reached

calebjmatthews · January 3, 2020, 6:08pm

I finished the Certbot process successfully (and foolishly selected to reroute HTTP traffic to HTTPS), but my site now does not load, although it can still be accessed by navigating to the naked IP address (167.172.248.24), which seems indicate that nginx is running at least somewhat successfully.

It also sounds like similar issues are often caused by the firewall, but I’ve made a ufw exception for both port 443 and nginx HTTPS traffic. Here’s the result of ufw status:

To                     Action      From
--                         ------      ----
OpenSSH                    ALLOW       Anywhere                  
3000/tcp                   ALLOW       Anywhere                  
3001/tcp                   ALLOW       Anywhere                  
8080/tcp                   ALLOW       Anywhere                  
Nginx HTTP                 ALLOW       Anywhere                  
Nginx HTTPS                ALLOW       Anywhere                  
443                        ALLOW       Anywhere                  
OpenSSH (v6)               ALLOW       Anywhere (v6)             
3000/tcp (v6)              ALLOW       Anywhere (v6)             
3001/tcp (v6)              ALLOW       Anywhere (v6)             
8080/tcp (v6)              ALLOW       Anywhere (v6)             
Nginx HTTP (v6)            ALLOW       Anywhere (v6)             
Nginx HTTPS (v6)           ALLOW       Anywhere (v6)             
443 (v6)                   ALLOW       Anywhere (v6)

My domain is: newsummer.co

My web server is (include version): nginx/1.14.0

The operating system my web server runs on is (include version): Ubuntu 18.04.3 (LTS) x64

My hosting provider, if applicable, is: Digital Ocean

I can login to a root shell on my machine (yes or no, or I don’t know): Yes

I’m using a control panel to manage my site (no, or provide the name and version of the control panel): No

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you’re using Certbot): certbot 0.31.0

Thanks in advance for any help!

mnordhoff · January 3, 2020, 6:43pm

Do you have a DigitalOcean Cloud Firewall blocking port 443?

Those might be duplicative. I don't know if that could cause problems.

JuergenAuer · January 3, 2020, 6:50pm

Hi @calebjmatthews

there are older checks of your domain, ~~ one hour old - https://check-your-website.server-daten.de/?q=newsummer.co

http works, https has a timeout.

So first question:

Works your https internal?

curl https://newsummer.co

from a console?

calebjmatthews · January 3, 2020, 7:21pm

Thanks for the quick reply! From a console SSHing into the Digital Ocean droplet, I get the following result almost immediately:

<!DOCTYPE html>
<html lang="en">
	<head>
		<title>New Summer</title>
		<meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

		<base href="/">
	</head>
	<body>

		<div id="root"></div>

		<script src="dist/main.js"></script>

	</body>
</html>

This is the index page for my app. What does this mean?

JuergenAuer · January 3, 2020, 7:24pm

Your https works internal. So it's a routing / firewall problem.

calebjmatthews · January 3, 2020, 7:31pm

Excellent, that’s good to know. It seems more likely that it’s a routing problem to me, any idea whether this would be an issue with the nginx sites-available config file?

calebjmatthews · January 3, 2020, 7:36pm

Thanks for weighing in @mnordhoff!

It looks like my Digital Ocean cloud firewall is not turned on. When you’re wondering about those rules being duplicative, are you concerned that having both standard and (v6) rules could be an issue? Or that having both nginx HTTPS and port 443 rules could be an issue?

JuergenAuer · January 3, 2020, 7:37pm

What says

nginx -T

calebjmatthews · January 3, 2020, 7:39pm

@JuergenAuer thanks for the continued help. Here it is:

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# configuration file /etc/nginx/nginx.conf:
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
        # multi_accept on;
}

http {

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        # server_tokens off;

        # server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

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


        ##
        # Gzip Settings
        ##

        gzip on;

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml appl$

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}

#mail {
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
# 
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
# 
#       server {
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
# 
#       server {
#               listen     localhost:143;
#               protocol   imap;
#               proxy      on;
#       }
#}



# configuration file /etc/nginx/modules-enabled/50-mod-http-geoip.conf:
load_module modules/ngx_http_geoip_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-http-image-filter.conf:
load_module modules/ngx_http_image_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-http-xslt-filter.conf:
load_module modules/ngx_http_xslt_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-mail.conf:
load_module modules/ngx_mail_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-stream.conf:
load_module modules/ngx_stream_module.so;

# configuration file /etc/nginx/mime.types:

types {
    text/html                             html htm shtml;
    text/css                              css;
    text/xml                              xml;
    image/gif                             gif;
    image/jpeg                            jpeg jpg;
    application/javascript                js;
    application/atom+xml                  atom;
    application/rss+xml                   rss;

    text/mathml                           mml;
    text/plain                            txt;
    text/vnd.sun.j2me.app-descriptor      jad;
    text/vnd.wap.wml                      wml;
    text/x-component                      htc;

    image/png                             png;
    image/tiff                            tif tiff;
    image/vnd.wap.wbmp                    wbmp;
    image/x-icon                          ico;
    image/x-jng                           jng;
    image/x-ms-bmp                        bmp;
    image/svg+xml                         svg svgz;
    image/webp                            webp;

    application/font-woff                 woff;
    application/java-archive              jar war ear;
    application/json                      json;
    application/mac-binhex40              hqx;
    application/msword                    doc;
    application/pdf                       pdf;
    application/postscript                ps eps ai;
    application/rtf                       rtf;
    application/vnd.apple.mpegurl         m3u8;
    application/vnd.ms-excel              xls;
    application/vnd.ms-fontobject         eot;
    application/vnd.ms-powerpoint         ppt;
    application/vnd.wap.wmlc              wmlc;
    application/vnd.google-earth.kml+xml  kml;
    application/vnd.google-earth.kmz      kmz;
    application/x-7z-compressed           7z;
    application/x-cocoa                   cco;
    application/x-java-archive-diff       jardiff;
    application/x-java-jnlp-file          jnlp;
    application/x-makeself                run;
    application/x-perl                    pl pm;
    application/x-pilot                   prc pdb;
    application/x-rar-compressed          rar;
    application/x-redhat-package-manager  rpm;
    application/x-sea                     sea;
    application/x-shockwave-flash         swf;
    application/x-stuffit                 sit;
    application/x-tcl                     tcl tk;
    application/x-x509-ca-cert            der pem crt;
    application/x-xpinstall               xpi;
    application/xhtml+xml                 xhtml;
    application/xspf+xml                  xspf;
    application/zip                       zip;

    application/octet-stream              bin exe dll;
    application/octet-stream              deb;
    application/octet-stream              dmg;
    application/octet-stream              iso img;
    application/octet-stream              msi msp msm;

    application/vnd.openxmlformats-officedocument.wordprocessingml.document    docx;
    application/vnd.openxmlformats-officedocument.spreadsheetml.sheet          xlsx;
    application/vnd.openxmlformats-officedocument.presentationml.presentation  pptx;

    audio/midi                            mid midi kar;
    audio/mpeg                            mp3;
    audio/ogg                             ogg;
    audio/x-m4a                           m4a;
    audio/x-realaudio                     ra;

    video/3gpp                            3gpp 3gp;
    video/mp2t                            ts;
    video/mp4                             mp4;
    video/mpeg                            mpeg mpg;
    video/quicktime                       mov;
    video/webm                            webm;
    video/x-flv                           flv;
    video/x-m4v                           m4v;
    video/x-mng                           mng;
    video/x-ms-asf                        asx asf;
    video/x-ms-wmv                        wmv;
    video/x-msvideo                       avi;
}

# configuration file /etc/nginx/sites-enabled/default:
##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
        listen 80 default_server;
        listen [::]:80 default_server;

        # SSL configuration
        #
        # listen 443 ssl default_server;
        # listen [::]:443 ssl default_server;
        #
        # Note: You should disable gzip for SSL traffic.
        # See: https://bugs.debian.org/773332
        #
        # Read up on ssl_ciphers to ensure a secure configuration.
        # See: https://bugs.debian.org/765782
        #
        # Self signed certs generated by the ssl-cert package
        # Don't use them in a production server!
        #
        # include snippets/snakeoil.conf;

        root /var/www/html;

        # Add index.php to the list if you are using PHP
        index index.html index.htm index.nginx-debian.html;

        server_name _;

        location / {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
	        proxy_pass http://localhost:8080;
        	proxy_http_version 1.1;
	        proxy_set_header Upgrade $http_upgrade;
        	proxy_set_header Connection 'upgrade';
	        proxy_set_header Host $host;
        	proxy_cache_bypass $http_upgrade;
        }

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #       include snippets/fastcgi-php.conf;
        #
        #       # With php7.0-cgi alone:
        #       fastcgi_pass 127.0.0.1:9000;
        #       # With php7.0-fpm:
        #       fastcgi_pass unix:/run/php/php7.0-fpm.sock;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #       deny all;
        #}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
#       listen 80;
#       listen [::]:80;
#
#       server_name example.com;
#
#       root /var/www/example.com;
#       index index.html;
#
#       location / {
#               try_files $uri $uri/ =404;
#       }
#}

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

        # SSL configuration
        #
        # listen 443 ssl default_server;
        # listen [::]:443 ssl default_server;
        #
        # Note: You should disable gzip for SSL traffic.
        # See: https://bugs.debian.org/773332
        #
        # Read up on ssl_ciphers to ensure a secure configuration.
        # See: https://bugs.debian.org/765782
        #
        # Self signed certs generated by the ssl-cert package
        # Don't use them in a production server!
        #
        # include snippets/snakeoil.conf;

        root /var/www/html;

        # Add index.php to the list if you are using PHP
        index index.html index.htm index.nginx-debian.html;
    server_name newsummer.co; # managed by Certbot


        location / {
                # First attempt to serve request as file, then
                # as directory, then fall back to displaying a 404.
	        proxy_pass http://localhost:8080;
        	proxy_http_version 1.1;
	        proxy_set_header Upgrade $http_upgrade;
        	proxy_set_header Connection 'upgrade';
	        proxy_set_header Host $host;
        	proxy_cache_bypass $http_upgrade;
        }

        # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        #location ~ \.php$ {
        #       include snippets/fastcgi-php.conf;
        #
        #       # With php7.0-cgi alone:
        #       fastcgi_pass 127.0.0.1:9000;
        #       # With php7.0-fpm:
        #       fastcgi_pass unix:/run/php/php7.0-fpm.sock;
        #}

        # deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        #location ~ /\.ht {
        #       deny all;
        #}


    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/newsummer.co/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/newsummer.co/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}
# configuration file /etc/letsencrypt/options-ssl-nginx.conf:
# This file contains important security parameters. If you modify this file
# manually, Certbot will be unable to automatically provide future security
# updates. Instead, Certbot will print and log an error message with a path to
# the up-to-date file that you will need to refer to when manually updating
# this file.

ssl_session_cache shared:le_nginx_SSL:1m;
ssl_session_timeout 1440m;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;

ssl_ciphers "ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS";

mnordhoff · January 3, 2020, 7:45pm

Are you sure the IP address (167.172.248.24) is correct?

What does "sudo iptables-save" output?

The latter.

(IPv4 and IPv6 rules are separate, and having them both is necessary if you're using both [which your site isn't].)

calebjmatthews · January 3, 2020, 7:50pm

Yeah, you can even navigate to the site successfully using that naked IP address in an address bar.

The following:
# Generated by iptables-save v1.6.1 on Fri Jan 3 19:48:32 2020

*nat

:PREROUTING ACCEPT [1153:59466]

:INPUT ACCEPT [148:8078]

:OUTPUT ACCEPT [61:3946]

:POSTROUTING ACCEPT [61:3946]

-A PREROUTING -d 167.172.248.24/32 -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 9192

COMMIT

# Completed on Fri Jan 3 19:48:32 2020

# Generated by iptables-save v1.6.1 on Fri Jan 3 19:48:32 2020

*filter

:INPUT DROP [627:32287]

:FORWARD DROP [0:0]

:OUTPUT ACCEPT [0:0]

:ufw-after-forward - [0:0]

:ufw-after-input - [0:0]

:ufw-after-logging-forward - [0:0]

:ufw-after-logging-input - [0:0]

:ufw-after-logging-output - [0:0]

:ufw-after-output - [0:0]

:ufw-before-forward - [0:0]

:ufw-before-input - [0:0]

:ufw-before-logging-forward - [0:0]

:ufw-before-logging-input - [0:0]

:ufw-before-logging-output - [0:0]

:ufw-before-output - [0:0]

:ufw-logging-allow - [0:0]

:ufw-logging-deny - [0:0]

:ufw-not-local - [0:0]

:ufw-reject-forward - [0:0]

:ufw-reject-input - [0:0]

:ufw-reject-output - [0:0]

:ufw-skip-to-policy-forward - [0:0]

:ufw-skip-to-policy-input - [0:0]

:ufw-skip-to-policy-output - [0:0]

:ufw-track-forward - [0:0]

:ufw-track-input - [0:0]

:ufw-track-output - [0:0]

:ufw-user-forward - [0:0]

:ufw-user-input - [0:0]

:ufw-user-limit - [0:0]

:ufw-user-limit-accept - [0:0]

:ufw-user-logging-forward - [0:0]

:ufw-user-logging-input - [0:0]

:ufw-user-logging-output - [0:0]

:ufw-user-output - [0:0]

-A INPUT -j ufw-before-logging-input

-A INPUT -j ufw-before-input

-A INPUT -j ufw-after-input

-A INPUT -j ufw-after-logging-input

-A INPUT -j ufw-reject-input

-A INPUT -j ufw-track-input

-A FORWARD -j ufw-before-logging-forward

-A FORWARD -j ufw-before-forward

-A FORWARD -j ufw-after-forward

-A FORWARD -j ufw-after-logging-forward

-A FORWARD -j ufw-reject-forward

-A FORWARD -j ufw-track-forward

-A OUTPUT -j ufw-before-logging-output

-A OUTPUT -j ufw-before-output

-A OUTPUT -j ufw-after-output

-A OUTPUT -j ufw-after-logging-output

-A OUTPUT -j ufw-reject-output

-A OUTPUT -j ufw-track-output

-A ufw-after-input -p udp -m udp --dport 137 -j ufw-skip-to-policy-input

-A ufw-after-input -p udp -m udp --dport 138 -j ufw-skip-to-policy-input

-A ufw-after-input -p tcp -m tcp --dport 139 -j ufw-skip-to-policy-input

-A ufw-after-input -p tcp -m tcp --dport 445 -j ufw-skip-to-policy-input

-A ufw-after-input -p udp -m udp --dport 67 -j ufw-skip-to-policy-input

-A ufw-after-input -p udp -m udp --dport 68 -j ufw-skip-to-policy-input

-A ufw-after-input -m addrtype --dst-type BROADCAST -j ufw-skip-to-policy-input

-A ufw-after-logging-forward -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW BLOCK] "

-A ufw-after-logging-input -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW BLOCK] "

-A ufw-before-forward -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

-A ufw-before-forward -p icmp -m icmp --icmp-type 3 -j ACCEPT

-A ufw-before-forward -p icmp -m icmp --icmp-type 11 -j ACCEPT

-A ufw-before-forward -p icmp -m icmp --icmp-type 12 -j ACCEPT

-A ufw-before-forward -p icmp -m icmp --icmp-type 8 -j ACCEPT

-A ufw-before-forward -j ufw-user-forward

-A ufw-before-input -i lo -j ACCEPT

-A ufw-before-input -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

-A ufw-before-input -m conntrack --ctstate INVALID -j ufw-logging-deny

-A ufw-before-input -m conntrack --ctstate INVALID -j DROP

-A ufw-before-input -p icmp -m icmp --icmp-type 3 -j ACCEPT

-A ufw-before-input -p icmp -m icmp --icmp-type 11 -j ACCEPT

-A ufw-before-input -p icmp -m icmp --icmp-type 12 -j ACCEPT

-A ufw-before-input -p icmp -m icmp --icmp-type 8 -j ACCEPT

-A ufw-before-input -p udp -m udp --sport 67 --dport 68 -j ACCEPT

-A ufw-before-input -j ufw-not-local

-A ufw-before-input -d 224.0.0.251/32 -p udp -m udp --dport 5353 -j ACCEPT

-A ufw-before-input -d 239.255.255.250/32 -p udp -m udp --dport 1900 -j ACCEPT

-A ufw-before-input -j ufw-user-input

-A ufw-before-output -o lo -j ACCEPT

-A ufw-before-output -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT

-A ufw-before-output -j ufw-user-output

-A ufw-logging-allow -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW ALLOW] "

-A ufw-logging-deny -m conntrack --ctstate INVALID -m limit --limit 3/min --limit-burst 10 -j RETURN

-A ufw-logging-deny -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW BLOCK] "

-A ufw-not-local -m addrtype --dst-type LOCAL -j RETURN

-A ufw-not-local -m addrtype --dst-type MULTICAST -j RETURN

-A ufw-not-local -m addrtype --dst-type BROADCAST -j RETURN

-A ufw-not-local -m limit --limit 3/min --limit-burst 10 -j ufw-logging-deny

-A ufw-not-local -j DROP

-A ufw-skip-to-policy-forward -j DROP

-A ufw-skip-to-policy-input -j DROP

-A ufw-skip-to-policy-output -j ACCEPT

-A ufw-track-output -p tcp -m conntrack --ctstate NEW -j ACCEPT

-A ufw-track-output -p udp -m conntrack --ctstate NEW -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 22 -m comment --comment "\'dapp_OpenSSH\'" -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 3000 -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 3001 -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 8080 -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 80 -m comment --comment "\'dapp_Nginx%20HTTP\'" -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 443 -m comment --comment "\'dapp_Nginx%20HTTPS\'" -j ACCEPT

-A ufw-user-input -p tcp -m tcp --dport 443 -j ACCEPT

-A ufw-user-input -p udp -m udp --dport 443 -j ACCEPT

-A ufw-user-limit -m limit --limit 3/min -j LOG --log-prefix "[UFW LIMIT BLOCK] "

-A ufw-user-limit -j REJECT --reject-with icmp-port-unreachable

-A ufw-user-limit-accept -j ACCEPT

COMMIT

# Completed on Fri Jan 3 19:48:32 2020

Thanks for the clarification. Unfortunately removing either of these doesn't resolve the issue; removing the 443 rule does seemingly nothing, and removing the nginx rules (I tried removing both HTTP and HTTPS) no longer serves the site on HTTP.

JuergenAuer · January 3, 2020, 7:50pm

There

is no ip address used, that's good. So -> firewall or another blocking instance.

PS:

There is the same picture - only http works, https not - https://check-your-website.server-daten.de/?q=167.172.248.24

calebjmatthews · January 3, 2020, 7:55pm

@JuergenAuer Any idea what the firewall or blocking instance could be? UFW seems to be configured to allow HTTPS traffic and port 443 traffic, but I tried disabling it entirely and accessing the site via HTTPS still doesn’t work.

mnordhoff · January 3, 2020, 8:12pm

calebjmatthews:

*nat
:PREROUTING ACCEPT [1153:59466]
:INPUT ACCEPT [148:8078]
:OUTPUT ACCEPT [61:3946]
:POSTROUTING ACCEPT [61:3946]
-A PREROUTING -d 167.172.248.24/32 -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 9192

There's a rule in the nat table redirecting port 443 to port 9192. So the traffic is getting blocked because there isn't another rule allowing port 9192. Additionally, since Nginx probably isn't listening on port 9192, that probably wouldn't work anyway.

Your site will likely start working if you delete the NAT rule.

Do you remember what it was created for? If it was being used for something, you might need to do something to fix whatever that was.

calebjmatthews · January 3, 2020, 8:36pm

Excellent catch @mnordhoff, I didn’t see that rule related to 443 redirecting at all! The Digital Ocean droplet I’m using is very new and hasn’t been customized hardly at all, so I have no idea where that NAT rule could have come from. I’m trying to remove it now, but I’m having a hard time seeing how I identify which NAT rule contains the redirect, is it part of the POSTROUTING rule on the previous line? Thanks!

mnordhoff · January 3, 2020, 8:43pm

You should be able to remove it with:

sudo iptables -t raw -D PREROUTING -d 167.172.248.24/32 -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 9192

or, I think:

sudo iptables -t raw -D PREROUTING 1

Of course, if something is going to recreate it next time you reboot…

calebjmatthews · January 3, 2020, 9:02pm

Just before receiving your message I just removed the rule with:

sudo iptables -t nat -D PREROUTING 1

And that solved the issue! I’m extremely grateful for your help. I’m also curious whether there’s something that will re-emplement the rule on reboot, like you wondered. I’m going to try to reboot now and see what happens.

Edit: Even after rebooting, the site is still correctly served using HTTPS. Success!

system · February 2, 2020, 9:02pm

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