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Port 1227 (dns2go)

IANA assigns port 1227 to dns2go: DNS2Go.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
dns2go TCP DNS2Go Deerfield Communications Inc -
dns2go UDP DNS2Go Deerfield Communications Inc -

Registry dates for this port: last modified 2015-07-15.

Check what is listening on port 1227

Linux: is anything listening on TCP 1227?
sudo ss -tlnp 'sport = :1227'
Linux: UDP 1227
sudo ss -ulnp 'sport = :1227'
Linux / macOS: which process owns the port
sudo lsof -nP -i :1227
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':1227 '
Windows (Command Prompt)
netstat -ano | findstr :1227
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 1227 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 1227
From Windows
Test-NetConnection HOST -Port 1227
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 1227

Block port 1227 in the firewall

ufw
sudo ufw deny 1227/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 1227 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 1227 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 1227' -Direction Inbound -Protocol TCP -LocalPort 1227 -Action Block
ufw
sudo ufw deny 1227/udp
iptables
sudo iptables -A INPUT -p udp --dport 1227 -j DROP
nftables
sudo nft add rule inet filter input udp dport 1227 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 1227' -Direction Inbound -Protocol UDP -LocalPort 1227 -Action Block

Related ports

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