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Port 3515 (must-backplane)

IANA assigns port 3515 to must-backplane: MUST Backplane.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
must-backplane TCP MUST Backplane Rick Stefanik -
must-backplane UDP MUST Backplane Rick Stefanik -

Registry dates for this port: registered 2002-05.

Check what is listening on port 3515

Linux: is anything listening on TCP 3515?
sudo ss -tlnp 'sport = :3515'
Linux: UDP 3515
sudo ss -ulnp 'sport = :3515'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3515
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3515 '
Windows (Command Prompt)
netstat -ano | findstr :3515
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3515 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3515
From Windows
Test-NetConnection HOST -Port 3515
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3515

Block port 3515 in the firewall

ufw
sudo ufw deny 3515/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3515 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3515 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3515' -Direction Inbound -Protocol TCP -LocalPort 3515 -Action Block
ufw
sudo ufw deny 3515/udp
iptables
sudo iptables -A INPUT -p udp --dport 3515 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3515 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3515' -Direction Inbound -Protocol UDP -LocalPort 3515 -Action Block

Related ports

3513arcpd3514must-p2p3516smartcard-port3517802-11-iapp

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