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Port 107 (rtelnet)

IANA assigns port 107 to rtelnet: Remote Telnet Service.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
rtelnet TCP Remote Telnet Service Jon Postel -
rtelnet UDP Remote Telnet Service Jon Postel -

Check what is listening on port 107

Linux: is anything listening on TCP 107?
sudo ss -tlnp 'sport = :107'
Linux: UDP 107
sudo ss -ulnp 'sport = :107'
Linux / macOS: which process owns the port
sudo lsof -nP -i :107
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':107 '
Windows (Command Prompt)
netstat -ano | findstr :107
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 107 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 107
From Windows
Test-NetConnection HOST -Port 107
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 107

Block port 107 in the firewall

ufw
sudo ufw deny 107/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 107 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 107 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 107' -Direction Inbound -Protocol TCP -LocalPort 107 -Action Block
ufw
sudo ufw deny 107/udp
iptables
sudo iptables -A INPUT -p udp --dport 107 -j DROP
nftables
sudo nft add rule inet filter input udp dport 107 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 107' -Direction Inbound -Protocol UDP -LocalPort 107 -Action Block

Related ports

105cso, csnet-ns1063com-tsmux108snagas109pop2

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