How to disable FTP port (Debian)? - nginx

Question

I am newbie in Debian. I have open FTP port (21) on Debian 6 (http server of the system is Nginx). How I can stop or disable the port via service or somehow yet? The command /etc/init.d/proftpd stop is not working, it shows in console bash: /etc/init.d/proftpd: No such file or directory because proftpd is absent.

Answer 1

Inputing this command netstat -tnlp, you can find which process is running on port 21.
Then you can some work by youself.

Answer 2

If you are to lazy to stop the service from running you can write an iptables rule
sbin/iptables -A INPUT -p tcp --destination-port {PORT-NUMBER-HERE} -j DROP

Answer 3

Start by checking if your port is listening
sudo ss -tulnp | grep LISTEN
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
tcp LISTEN 0 5 127.0.0.1:29754 0.0.0.0:* users:(("vpnagentd",pid=960,fd=4))
tcp LISTEN 0 128 0.0.0.0:17500 0.0.0.0:* users:(("dropbox",pid=3129583,fd=48))
tcp LISTEN 0 50 0.0.0.0:445 0.0.0.0:* users:(("smbd",pid=923696,fd=48))
tcp LISTEN 0 128 127.0.0.1:17600 0.0.0.0:* users:(("dropbox",pid=3129583,fd=67))
tcp LISTEN 0 128 127.0.0.1:17603 0.0.0.0:* users:(("dropbox",pid=3129583,fd=75))
tcp LISTEN 0 50 0.0.0.0:139 0.0.0.0:* users:(("smbd",pid=923696,fd=49))
tcp LISTEN 0 32 0.0.0.0:53 0.0.0.0:* users:(("dnsmasq",pid=1276,fd=7))
tcp LISTEN 0 32 0.0.0.0:21 0.0.0.0:* users:(("vsftpd",pid=1230,fd=3))
tcp LISTEN 0 128 0.0.0.0:22 0.0.0.0:* users:(("sshd",pid=43857,fd=3))
tcp LISTEN 0 128 127.0.0.1:631 0.0.0.0:* users:(("cupsd",pid=3138801,fd=7))
tcp LISTEN 0 128 [::]:17500 [::]:* users:(("dropbox",pid=3129583,fd=47))
tcp LISTEN 0 2 *:3389 *:* users:(("xrdp",pid=1306,fd=11))
tcp LISTEN 0 50 [::]:445 [::]:* users:(("smbd",pid=923696,fd=46))
tcp LISTEN 0 50 [::]:139 [::]:* users:(("smbd",pid=923696,fd=47))
tcp LISTEN 0 32 [::]:53 [::]:* users:(("dnsmasq",pid=1276,fd=9))
tcp LISTEN 0 128 [::]:22 [::]:* users:(("sshd",pid=43857,fd=4))
tcp LISTEN 0 2 [::1]:3350 [::]:* users:(("xrdp-sesman",pid=1295,fd=7))
tcp LISTEN 0 128 [::1]:631 [::]:* users:(("cupsd",pid=3138801,fd=6))
So, you see in port 21 you have service vsftpd listening.
You can check the status:
sudo service vsftpd status
● vsftpd.service - vsftpd FTP server
Loaded: loaded (/lib/systemd/system/vsftpd.service; enabled; vendor preset: enabled)
Active: active (running) since Tue 2022-07-19 09:42:45 EDT; 2 months 15 days ago
Main PID: 1230 (vsftpd)
Tasks: 1 (limit: 38363)
Memory: 972.0K
CPU: 7ms
CGroup: /system.slice/vsftpd.service
└─1230 /usr/sbin/vsftpd /etc/vsftpd.conf
Now, you can block the port with the firewall (for example you can use ufw), or stop the service
$ sudo service vsftpd stop
$ sudo service vsftpd status
● vsftpd.service - vsftpd FTP server
Loaded: loaded (/lib/systemd/system/vsftpd.service; enabled; vendor preset: enabled)
Active: inactive (dead) since Mon 2022-10-03 10:55:50 EDT; 9s ago
Process: 1230 ExecStart=/usr/sbin/vsftpd /etc/vsftpd.conf (code=killed, signal=TERM)
Main PID: 1230 (code=killed, signal=TERM)
CPU: 7ms
Oct 03 10:55:50 Tuxy systemd[1]: Stopping vsftpd FTP server...
Oct 03 10:55:50 Tuxy systemd[1]: vsftpd.service: Succeeded.
Oct 03 10:55:50 Tuxy systemd[1]: Stopped vsftpd FTP server.
So, in summary. Install ufw. Unblock only ports you are going to use (ssh, etc). Start only the services you are going to use. (sudo service *** start/stop)
good luck