HTTPfy

Port 6421 (nim-wan)

IANA assigns port 6421 to nim-wan: NIM_WAN.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
nim-wan TCP NIM_WAN Rik Ditter -
nim-wan UDP NIM_WAN Rik Ditter -

Registry dates for this port: registered 2006-02.

Check what is listening on port 6421

Linux: is anything listening on TCP 6421?
sudo ss -tlnp 'sport = :6421'
Linux: UDP 6421
sudo ss -ulnp 'sport = :6421'
Linux / macOS: which process owns the port
sudo lsof -nP -i :6421
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':6421 '
Windows (Command Prompt)
netstat -ano | findstr :6421
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 6421 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 6421
From Windows
Test-NetConnection HOST -Port 6421
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 6421

Block port 6421 in the firewall

ufw
sudo ufw deny 6421/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 6421 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 6421 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 6421' -Direction Inbound -Protocol TCP -LocalPort 6421 -Action Block
ufw
sudo ufw deny 6421/udp
iptables
sudo iptables -A INPUT -p udp --dport 6421 -j DROP
nftables
sudo nft add rule inet filter input udp dport 6421 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 6421' -Direction Inbound -Protocol UDP -LocalPort 6421 -Action Block

Related ports

6419svdrp, svdrp-disc6420nim-vdrshell6432PgBouncer6440heliosd

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