Port 990: FTPS
TCP 990 is the port for FTP over implicit TLS. Acceptable for legacy file exchange; SFTP on 22 is simpler to firewall.
| Service | FTP over implicit TLS |
|---|---|
| Protocol | TCP |
| Exposure risk | Medium: expose with care |
| Range | Well-known (0–1023): binding needs root/admin on Unix |
What port 990 does
FTP with TLS from the first byte on the control channel. Passive data ports still need to be opened separately.
Should port 990 be open?
Acceptable for legacy file exchange; SFTP on 22 is simpler to firewall.
Find what's listening on port 990
- Linux:
sudo ss -tulpn | grep :990 - macOS:
sudo lsof -nP -i :990 - Windows:
netstat -ano | findstr :990, then look up the PID in Task Manager.
Open or block it in a firewall
- ufw:
sudo ufw allow 990/tcp(ordeny) - firewalld:
sudo firewall-cmd --add-port=990/tcp --permanent && sudo firewall-cmd --reload - Windows:
New-NetFirewallRule -DisplayName "Port 990" -Direction Inbound -Protocol TCP -LocalPort 990 -Action Allow
Port assignment per the IANA Service Name and Transport Protocol Port Number Registry. Test several ports at once with the port scanner, or any port with the open port checker.
Questions about port 990
What is port 990 used for?
FTP over implicit TLS. FTP with TLS from the first byte on the control channel. Passive data ports still need to be opened separately.
Is port 990 TCP or UDP?
TCP. FTPS uses TCP port 990.
Is it safe to open port 990?
Medium: expose with care. Acceptable for legacy file exchange; SFTP on 22 is simpler to firewall.
How do I check if port 990 is open?
Use the checker on this page: it connects to your host on TCP 990 from the internet. Locally, run
nc -vz host 990 (macOS/Linux) or Test-NetConnection host -Port 990 (PowerShell). To see what is listening on your own machine, run ss -tulpn | grep :990 (Linux) or netstat -ano | findstr :990 (Windows).