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Port 375 (hassle)

IANA assigns port 375 to hassle: Hassle.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
hassle TCP Hassle Reinhard Doelz -
hassle UDP Hassle Reinhard Doelz -

Check what is listening on port 375

Linux: is anything listening on TCP 375?
sudo ss -tlnp 'sport = :375'
Linux: UDP 375
sudo ss -ulnp 'sport = :375'
Linux / macOS: which process owns the port
sudo lsof -nP -i :375
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':375 '
Windows (Command Prompt)
netstat -ano | findstr :375
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 375 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 375
From Windows
Test-NetConnection HOST -Port 375
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 375

Block port 375 in the firewall

ufw
sudo ufw deny 375/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 375 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 375 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 375' -Direction Inbound -Protocol TCP -LocalPort 375 -Action Block
ufw
sudo ufw deny 375/udp
iptables
sudo iptables -A INPUT -p udp --dport 375 -j DROP
nftables
sudo nft add rule inet filter input udp dport 375 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 375' -Direction Inbound -Protocol UDP -LocalPort 375 -Action Block

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