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Port 3765 (rtraceroute)

IANA assigns port 3765 to rtraceroute: Remote Traceroute.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
rtraceroute TCP Remote Traceroute A Blake Cooper -
rtraceroute UDP Remote Traceroute A Blake Cooper -

Registry dates for this port: registered 2003-06.

Check what is listening on port 3765

Linux: is anything listening on TCP 3765?
sudo ss -tlnp 'sport = :3765'
Linux: UDP 3765
sudo ss -ulnp 'sport = :3765'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3765
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3765 '
Windows (Command Prompt)
netstat -ano | findstr :3765
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3765 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3765
From Windows
Test-NetConnection HOST -Port 3765
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3765

Block port 3765 in the firewall

ufw
sudo ufw deny 3765/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3765 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3765 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3765' -Direction Inbound -Protocol TCP -LocalPort 3765 -Action Block
ufw
sudo ufw deny 3765/udp
iptables
sudo iptables -A INPUT -p udp --dport 3765 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3765 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3765' -Direction Inbound -Protocol UDP -LocalPort 3765 -Action Block

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3763xo-wave3764mni-prot-rout3766sitewatch-s3767listmgr-port

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