My networking service has failed to restart, first after some configuration, then after a reboot. I'd like to know why and how to resolve the issue.
As I'm fairly new to Linux, especially when it comes to complex configuration, I'll try to explain what I did to get so stuck. I have a virtual machine running Debian 9. On it, I installed Nginx in an attempt to run Gunicorn and Flask for a Python web app. I managed to set up a simple server and install SSL Certificates. Even Gunicorn worked on a subdomain. But the certificates, which were automatically installed and configured by Certbot, didn't include this subdomain. So I deleted the certificate, configured the server back to allow for another certificate install, this time a
certonly one - I figured I'd gotten the configuration right. The certificate was installed, but approximately at that time my server stopped responding completely, as if it's blocking all traffic.
Trying a number of configurations ranging from my full subdomain conf to a minimalist default configuration, all of them pass
nginx -t and restart fine,
ufw allows all the correct ports, namely 80, 443 and 2222, which I use for ssh. However,
curl my_machine.net refuses connections and
nmap displays only the ssh port.
Below is the log of
journalctl -xe, should that provide any information. Where could I begin debugging? I'm pretty sure it was either Nginx, Certbot or some other event not triggered by me (at least intentionally) that started this.
systemctl --all shows no other services have failed, though some have their condition failed, which seems like a normal situation.
-- Unit networking.service has begun starting up. Jul 08 18:33:13 my_machine.net ifup: RTNETLINK answers: File exists Jul 08 18:33:13 my_machine.net ifup: ifup: failed to bring up eth0 Jul 08 18:33:13 my_machine.net systemd: networking.service: Main process exited, code=exited, status=1/FAILURE Jul 08 18:33:13 my_machine.net systemd: Failed to start Raise network interfaces. -- Subject: Unit networking.service has failed -- Defined-By: systemd -- Support: https://www.debian.org/support -- -- Unit networking.service has failed. -- -- The result is failed. Jul 08 18:33:13 my_machine.net systemd: networking.service: Unit entered failed state. Jul 08 18:33:13 my_machine.net systemd: networking.service: Failed with result 'exit-code'. Jul 08 18:33:13 my_machine.net sudo: pam_unix(sudo:session): session closed for user root Jul 08 18:33:21 my_machine.net kernel: [UFW BLOCK] IN=eth0 OUT= MAC=long_address SRC=short_address Jul 08 18:33:26 my_machine.net sudo: my_user : TTY=pts/0 ; PWD=/home/my_user ; USER=root ; COMMAND=/bin/journalctl - Jul 08 18:33:26 my_machine.net sudo: pam_unix(sudo:session): session opened for user root by my_user(uid=0)
- After a
dhclient -rand another reboot, a different error is shown:
RTNETLINK answers: Permission denied.
net.ipv6.conf.all.disable_ipv6 = 1, but before editing such a file I'd like to make sure what exact effect this has on the system
- I do have general internet connection, apparent from ssh and curling outwards, e.g.
- For what it's worth,
ping my_machine.networks, but I guess that ought to
- The output of
default via xx.xx.xx.1 dev eth0 onlink
xx.xx.xx.0/24 via xx.xx.xx.1 dev eth0