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Port 266 (sst)

IANA assigns port 266 to sst: SCSI on ST.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
sst TCP SCSI on ST Donald D Woelz -
sst UDP SCSI on ST Donald D Woelz -

Check what is listening on port 266

Linux: is anything listening on TCP 266?
sudo ss -tlnp 'sport = :266'
Linux: UDP 266
sudo ss -ulnp 'sport = :266'
Linux / macOS: which process owns the port
sudo lsof -nP -i :266
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':266 '
Windows (Command Prompt)
netstat -ano | findstr :266
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 266 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 266
From Windows
Test-NetConnection HOST -Port 266
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 266

Block port 266 in the firewall

ufw
sudo ufw deny 266/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 266 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 266 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 266' -Direction Inbound -Protocol TCP -LocalPort 266 -Action Block
ufw
sudo ufw deny 266/udp
iptables
sudo iptables -A INPUT -p udp --dport 266 -j DROP
nftables
sudo nft add rule inet filter input udp dport 266 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 266' -Direction Inbound -Protocol UDP -LocalPort 266 -Action Block

Related ports

264bgmp265x-bone-ctl267td-service268td-replica

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