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// Network services

Port 1870: SunSCALAR DNS Service

Port 1870 is assigned by IANA to sunscalar-dns (SunSCALAR DNS Service).

1870

How sunscalar-dns works

Network services
client:1870sunscalar-dnsresponse client:1870sunscalar-dnsresponse

The client sends a request to port 1870 and the sunscalar-dns service answers.

Transport
TCP · 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
Network services
01 Security

Is port 1870 dangerous?

We have no specific security note for port 1870. Its risk depends on the program actually listening on it. General advice for network services services:

  • Answer only the networks that need the service (no open resolvers, relays or reflectors).
  • UDP services can be abused for DDoS amplification: rate-limit or block them at the edge.
  • Disable legacy test services that have no use in production.
02 Registry

IANA registry entries for port 1870

ServicePortTransportDescriptionReferenceUpdated
sunscalar-dns 1870 TCP, UDP SunSCALAR DNS Service - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 1870, and is it reachable?

Linux

sudo ss -ltnup 'sport = :1870'      # process listening on 1870
sudo lsof -nP -i :1870

macOS

sudo lsof -nP -i :1870

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1870 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 1870
netstat -ano | findstr :1870

From another machine

nmap -p 1870 -sV <host>
sudo nmap -sU -p 1870 <host>
nc -zv <host> 1870

Block it in the firewall

sudo ufw deny 1870/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 1870" -Direction Inbound -LocalPort 1870 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 1870 used for?

Port 1870 is assigned by IANA to sunscalar-dns (SunSCALAR DNS Service).

Is port 1870 TCP or UDP?

Port 1870 is registered for TCP and UDP.

Is it safe to open port 1870?

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. Answer only the networks that need the service (no open resolvers, relays or reflectors).

How do I check if port 1870 is open?

On Linux run "ss -ltnup 'sport = :1870'", on macOS "lsof -nP -i :1870", and on Windows "netstat -ano | findstr :1870" to see the local process. From another machine, "nmap -p 1870 <host>" shows whether it is reachable.

05 Related
:53 DNS tcp · udp · moderate risk :135 MS RPC tcp · udp · high risk :123 NTP udp · tcp · moderate risk :67 DHCP server udp · tcp · moderate risk :111 rpcbind tcp · udp · high risk :9100 Raw printing (JetDirect) tcp · udp · high risk :631 IPP / CUPS tcp · udp · high risk :5353 mDNS udp · tcp · moderate risk

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