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Port 3531 (joltid)

IANA assigns port 3531 to joltid: Joltid.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
joltid TCP Joltid Ahti Heinla -
joltid UDP Joltid Ahti Heinla -

Registry dates for this port: registered 2002-06.

Check what is listening on port 3531

Linux: is anything listening on TCP 3531?
sudo ss -tlnp 'sport = :3531'
Linux: UDP 3531
sudo ss -ulnp 'sport = :3531'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3531
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3531 '
Windows (Command Prompt)
netstat -ano | findstr :3531
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3531 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3531
From Windows
Test-NetConnection HOST -Port 3531
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3531

Block port 3531 in the firewall

ufw
sudo ufw deny 3531/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3531 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3531 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3531' -Direction Inbound -Protocol TCP -LocalPort 3531 -Action Block
ufw
sudo ufw deny 3531/udp
iptables
sudo iptables -A INPUT -p udp --dport 3531 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3531 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3531' -Direction Inbound -Protocol UDP -LocalPort 3531 -Action Block

Related ports

3529jboss-iiop-ssl3530gf3532raven-rmp3533raven-rdp

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