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Port 6100 (synchronet-db)

IANA assigns port 6100 to synchronet-db: SynchroNet-db.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
synchronet-db TCP SynchroNet-db Arne Haugland -
synchronet-db UDP SynchroNet-db Arne Haugland -

Check what is listening on port 6100

Linux: is anything listening on TCP 6100?
sudo ss -tlnp 'sport = :6100'
Linux: UDP 6100
sudo ss -ulnp 'sport = :6100'
Linux / macOS: which process owns the port
sudo lsof -nP -i :6100
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':6100 '
Windows (Command Prompt)
netstat -ano | findstr :6100
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 6100 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 6100
From Windows
Test-NetConnection HOST -Port 6100
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 6100

Block port 6100 in the firewall

ufw
sudo ufw deny 6100/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 6100 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 6100 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 6100' -Direction Inbound -Protocol TCP -LocalPort 6100 -Action Block
ufw
sudo ufw deny 6100/udp
iptables
sudo iptables -A INPUT -p udp --dport 6100 -j DROP
nftables
sudo nft add rule inet filter input udp dport 6100 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 6100' -Direction Inbound -Protocol UDP -LocalPort 6100 -Action Block

Related ports

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