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Port 3269 (AD Global Catalog over TLS)

Global Catalog queries over LDAPS.

Registered (user) port, 1024-49151 TCP Directory and authentication Do not expose to the internet

What port 3269 is used for

Global Catalog queries over LDAPS.

Security: should port 3269 be open?

Do not expose to the internet. Internal only.

IANA assignment

Service nameProtoDescriptionAssigneeReference
msft-gc-ssl TCP Microsoft Global Catalog with LDAP/SSL Asaf Kashi -
msft-gc-ssl UDP Microsoft Global Catalog with LDAP/SSL Asaf Kashi -

Check what is listening on port 3269

Linux: is anything listening on TCP 3269?
sudo ss -tlnp 'sport = :3269'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3269
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3269 '
Windows (Command Prompt)
netstat -ano | findstr :3269
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3269 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3269
From Windows
Test-NetConnection HOST -Port 3269

Block port 3269 in the firewall

ufw
sudo ufw deny 3269/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3269 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3269 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3269' -Direction Inbound -Protocol TCP -LocalPort 3269 -Action Block

Related ports

3268AD Global Catalog636LDAPS3267ibm-dial-out3270verismart3271csoft-prev

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