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Port 4356 (qsnet-assist)

IANA assigns port 4356 to qsnet-assist: QSNet Assistant.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
qsnet-assist TCP QSNet Assistant - -
qsnet-assist UDP QSNet Assistant - -

Check what is listening on port 4356

Linux: is anything listening on TCP 4356?
sudo ss -tlnp 'sport = :4356'
Linux: UDP 4356
sudo ss -ulnp 'sport = :4356'
Linux / macOS: which process owns the port
sudo lsof -nP -i :4356
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':4356 '
Windows (Command Prompt)
netstat -ano | findstr :4356
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 4356 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 4356
From Windows
Test-NetConnection HOST -Port 4356
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 4356

Block port 4356 in the firewall

ufw
sudo ufw deny 4356/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 4356 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 4356 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 4356' -Direction Inbound -Protocol TCP -LocalPort 4356 -Action Block
ufw
sudo ufw deny 4356/udp
iptables
sudo iptables -A INPUT -p udp --dport 4356 -j DROP
nftables
sudo nft add rule inet filter input udp dport 4356 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 4356' -Direction Inbound -Protocol UDP -LocalPort 4356 -Action Block

Related ports

4354qsnet-trans4355qsnet-workst4357qsnet-cond4358qsnet-nucl

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