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Port 683 (corba-iiop)

IANA assigns port 683 to corba-iiop: CORBA IIOP.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
corba-iiop TCP CORBA IIOP - -
corba-iiop UDP CORBA IIOP - -

Check what is listening on port 683

Linux: is anything listening on TCP 683?
sudo ss -tlnp 'sport = :683'
Linux: UDP 683
sudo ss -ulnp 'sport = :683'
Linux / macOS: which process owns the port
sudo lsof -nP -i :683
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':683 '
Windows (Command Prompt)
netstat -ano | findstr :683
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 683 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 683
From Windows
Test-NetConnection HOST -Port 683
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 683

Block port 683 in the firewall

ufw
sudo ufw deny 683/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 683 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 683 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 683' -Direction Inbound -Protocol TCP -LocalPort 683 -Action Block
ufw
sudo ufw deny 683/udp
iptables
sudo iptables -A INPUT -p udp --dport 683 -j DROP
nftables
sudo nft add rule inet filter input udp dport 683 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 683' -Direction Inbound -Protocol UDP -LocalPort 683 -Action Block

Related ports

681entrust-aams682xfr684corba-iiop-ssl685mdc-portmapper

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.