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// Other services

Port 1027: IPv6 Behind NAT44 CPEs

Port 1027 is assigned by IANA to 6a44 (IPv6 Behind NAT44 CPEs).

1027

How 6a44 works

Other services
client:10276a44response client:10276a44response

The client sends a request to port 1027 and the 6a44 service answers.

Transport
UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Registered (1024-49151)
Category
Other services
01 Security

Is port 1027 dangerous?

We have no specific security note for port 1027. Its risk depends on the program actually listening on it. General advice for other services services:

  • Close the port if nothing on the host needs it.
  • Identify the process that listens on it (commands below) before opening it in a firewall.
  • Expose a service only to the networks that use it.
02 Registry

IANA registry entries for port 1027

ServicePortTransportDescriptionReferenceUpdated
6a44 1027 UDP IPv6 Behind NAT44 CPEs RFC 6751 2012-08-02
-1027-Reserved--

// source: IANA service name and port number registry

03 Check it

Which program uses port 1027, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1027'      # process listening on 1027
sudo lsof -nP -i :1027

macOS

sudo lsof -nP -i :1027

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1027 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1027
netstat -ano | findstr :1027

From another machine

nmap -p 1027 -sV <host>
sudo nmap -sU -p 1027 <host>
nc -zv <host> 1027

Block it in the firewall

sudo ufw deny 1027/udp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1027" -Direction Inbound -LocalPort 1027 -Protocol UDP -Action Block  # Windows
04 FAQ
What is port 1027 used for?

Port 1027 is assigned by IANA to 6a44 (IPv6 Behind NAT44 CPEs).

Is port 1027 TCP or UDP?

Port 1027 is registered for UDP.

Is it safe to open port 1027?

It depends on the program that listens on it. Open it only for a service you know and only to the networks that need it. Close the port if nothing on the host needs it.

How do I check if port 1027 is open?

On Linux run "ss -ltnup 'sport = :1027'", on macOS "lsof -nP -i :1027", and on Windows "netstat -ano | findstr :1027" to see the local process. From another machine, "nmap -p 1027 <host>" shows whether it is reachable.

05 Related
:4444 Metasploit default / krb524 tcp · udp · high risk :31337 Back Orifice / elite tcp · udp · high risk :1 TCP Port Service Multiplexer tcp · udp :5 Remote Job Entry tcp · udp :9 Discard tcp · udp · sctp · dccp :11 Active Users tcp · udp :17 Quote of the Day tcp · udp :18 Message Send Protocol (historic) tcp · udp

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