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Port 2323 (Telnet alternate)

Alternative Telnet port found on many IoT devices and DVRs.

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

What port 2323 is used for

Alternative Telnet port found on many IoT devices and DVRs.

Security: should port 2323 be open?

Do not expose to the internet. Scanned by Mirai-style botnets with default passwords; disable it.

IANA assignment

Service nameProtoDescriptionAssigneeReference
3d-nfsd TCP 3d-nfsd Mike Sherrill -
3d-nfsd UDP 3d-nfsd Mike Sherrill -

Check what is listening on port 2323

Linux: is anything listening on TCP 2323?
sudo ss -tlnp 'sport = :2323'
Linux / macOS: which process owns the port
sudo lsof -nP -i :2323
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':2323 '
Windows (Command Prompt)
netstat -ano | findstr :2323
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 2323 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 2323
From Windows
Test-NetConnection HOST -Port 2323

Block port 2323 in the firewall

ufw
sudo ufw deny 2323/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 2323 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 2323 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 2323' -Direction Inbound -Protocol TCP -LocalPort 2323 -Action Block

Related ports

23Telnet7547TR-069 (CWMP)2321rdlap2322ofsd2324cosmocall2325ansysli

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