Port 989 (FTPS (implicit, data))

Data channel for implicit FTPS in active mode.

Well-known (system) port, 0-1023 TCP File transfer and storage Expose only to trusted sources

What port 989 is used for

Data channel for implicit FTPS in active mode.

Expose only to trusted sources. Only needed with an FTPS server.

Service nameProtoDescriptionAssigneeReference

ftps-data TCP ftp protocol, data, over TLS/SSL - -

ftps-data UDP ftp protocol, data, over TLS/SSL - -

Linux: is anything listening on TCP 989?

sudo ss -tlnp 'sport = :989'

Linux / macOS: which process owns the port

sudo lsof -nP -i :989

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':989 '

Windows (Command Prompt)

netstat -ano | findstr :989

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 989 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 989

From Windows

Test-NetConnection HOST -Port 989

Replace 203.0.113.10 with the address or network you trust. With ufw, make sure the default incoming policy is deny.

ufw (one trusted source)

sudo ufw allow from 203.0.113.10 to any port 989 proto tcp

iptables

sudo iptables -A INPUT -p tcp --dport 989 -s 203.0.113.10 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 989 -j DROP

nftables

sudo nft add rule inet filter input ip saddr 203.0.113.10 tcp dport 989 accept
sudo nft add rule inet filter input tcp dport 989 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'TCP 989 trusted' -Direction Inbound -Protocol TCP -LocalPort 989 -RemoteAddress 203.0.113.10 -Action Allow

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.