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Port 151 (hems)

IANA assigns port 151 to hems: HEMS.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
hems TCP HEMS - -
hems UDP HEMS - -

Check what is listening on port 151

Linux: is anything listening on TCP 151?
sudo ss -tlnp 'sport = :151'
Linux: UDP 151
sudo ss -ulnp 'sport = :151'
Linux / macOS: which process owns the port
sudo lsof -nP -i :151
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':151 '
Windows (Command Prompt)
netstat -ano | findstr :151
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 151 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 151
From Windows
Test-NetConnection HOST -Port 151
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 151

Block port 151 in the firewall

ufw
sudo ufw deny 151/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 151 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 151 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 151' -Direction Inbound -Protocol TCP -LocalPort 151 -Action Block
ufw
sudo ufw deny 151/udp
iptables
sudo iptables -A INPUT -p udp --dport 151 -j DROP
nftables
sudo nft add rule inet filter input udp dport 151 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 151' -Direction Inbound -Protocol UDP -LocalPort 151 -Action Block

Related ports

149aed-512150sql-net152bftp153sgmp

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