HTTPfy

Port 3429 (gcsp)

IANA assigns port 3429 to gcsp: GCSP user port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
gcsp TCP GCSP user port Anirban Majumder -
gcsp UDP GCSP user port Anirban Majumder -

Registry dates for this port: registered 2002-03.

Check what is listening on port 3429

Linux: is anything listening on TCP 3429?
sudo ss -tlnp 'sport = :3429'
Linux: UDP 3429
sudo ss -ulnp 'sport = :3429'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3429
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3429 '
Windows (Command Prompt)
netstat -ano | findstr :3429
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3429 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3429
From Windows
Test-NetConnection HOST -Port 3429
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3429

Block port 3429 in the firewall

ufw
sudo ufw deny 3429/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3429 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3429 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3429' -Direction Inbound -Protocol TCP -LocalPort 3429 -Action Block
ufw
sudo ufw deny 3429/udp
iptables
sudo iptables -A INPUT -p udp --dport 3429 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3429 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3429' -Direction Inbound -Protocol UDP -LocalPort 3429 -Action Block

Related ports

3427websphere-snmp3428twcss3430ssdispatch3431ndl-als

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