Ubuntu – DigitalOcean Ubuntu droplet not serving port 80

portpythonUbuntu

I have a simple Python server on a DigitalOcean Ubuntu droplet that should serve the index.html file in the /dist folder:

port = 8000
os.chdir(os.path.join(os.path.dirname(__file__), 'dist'))
Handler = http.server.SimpleHTTPRequestHandler
httpd = socketserver.TCPServer(('', port), Handler)
print('Serving at port ', port)
httpd.serve_forever()

I have no cloud firewalls running on this box. I ran 'sudo ufw allow 80/tcp' to open the firewall and if I run ufw status it shows port 80 as being open to everybody. I ran 'sudo iptables -t nat -A PREROUTING -i eth0 -p tcp –dport 80 -j REDIRECT –to-port 8000' to redirect traffic from port 80 to port 8000.

If I run nmap from another box, the only open port is ssh on 22. Port 80 is filtered. Navigating to the host in my browser results in a connection timeout. Trying to serve directly from port 80 yields the same results. If I try nmap or netstat locally, the port shows open but the server crashes (connection reset by peer, no other useful error info). What could be causing this?

Best Answer

Turns out I had to enable the DigitalOcean firewall and set it up, otherwise it was just blocking all non-ssh connections.

Related Solutions

Ubuntu – Save changes to iptables

As far as I know Ubuntu uses UFW in the latest version, so most likely it doesn't have a SysV init script for iptables. If you don't feel comfortable with UFW, you may use sudo iptables-save > /etc/iptables.rules to store your current rules and then invoke sudo iptables-restore < /etc/iptables.rules from rc.local (for example) to restore the rules on startup.

Or, you can add your own init script for iptables as specified here:

#!/bin/sh -e
### BEGIN INIT INFO
# Provides:          iptables
# Required-Start:    mountvirtfs ifupdown $local_fs
# Default-Start:     S
# Default-Stop:      0 6
### END INIT INFO

# July 9, 2007
# James B. Crocker <ubuntu@james.crocker.name>
# Creative Commons Attribution - Share Alike 3.0 License (BY,SA)
# Script to load/unload/save iptables firewall settings.

PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin"

IPTABLES=/sbin/iptables
IPTABLES_SAVE=/sbin/iptables-save
IPTABLES_RESTORE=/sbin/iptables-restore

IPTABLES_CONFIG=/etc/iptables.conf

[ -x $IPTABLES ] || exit 0

. /lib/lsb/init-functions


case "$1" in
start)
    log_action_begin_msg "Starting firewall"
        type usplash_write >/dev/null 2>/dev/null && usplash_write "TIMEOUT 120" || true
    if $IPTABLES_RESTORE < $IPTABLES_CONFIG ; then
        log_action_end_msg $?
    else
    log_action_end_msg $?
    fi
        type usplash_write >/dev/null 2>/dev/null && usplash_write "TIMEOUT 15" || true
    ;;

stop)
    log_action_begin_msg "Saving current firewall configuration"
    if $IPTABLES_SAVE > $IPTABLES_CONFIG ; then
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi
    log_action_begin_msg "Flushing ALL firewall rules from chains!"
    if $IPTABLES -F ; then
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi
    log_action_begin_msg "Deleting ALL firewall chains [Warning: ACCEPTING ALL PORT SERVICES!]"
    if $IPTABLES -X ; then
        $IPTABLES -P INPUT ACCEPT
        $IPTABLES -P FORWARD ACCEPT
        $IPTABLES -P OUTPUT ACCEPT
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi
    ;;

save)
    log_action_begin_msg "Saving current firewall configuration"
    if $IPTABLES_SAVE > $IPTABLES_CONFIG ; then
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi
    ;;

force-reload|restart)
    log_action_begin_msg "Reloading firewall configuration [Warning: POTENTIAL NETWORK INSECURITY DURING RELOAD]"
    $IPTABLES -F
    $IPTABLES -X
    if $IPTABLES_RESTORE < $IPTABLES_CONFIG ; then
        log_action_end_msg $?
    else
        log_action_end_msg $?
    fi
    ;;

*)
    echo "Usage: /etc/init.d/iptables {start|stop|save|restart|force-reload}"
    exit 1
    ;;
esac

exit 0

Ubuntu – opening imap port 143 using iptables in ubuntu server

It doesn't look like your firewall is doing anything, the policies are all to ACCEPT and all of the rules are ACCEPT.

Try disabling your firewall and see what happens.

The error message your seeing says Connection refused this generally means that there isn't anything listening on the relevant port. Check your service is running and check that it's configured to listen on the correct interface and port.

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