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// Databases & caches

Port 635: RLZ DBase

Port 635 is assigned by IANA to rlzdbase (RLZ DBase).

635

How rlzdbase works

Databases & caches
app:635rlzdbase app:635rlzdbase

The application sends a SQL query to the rlzdbase server on port 635, which returns rows from its tables.

Transport
TCP · UDP
Exposure risk
not rated depends on the program listening
Encryption
Unknownnot stated by the registry
IANA status
Assigned1 registered service
Range
Well-known (0-1023)
Category
Databases & caches
01 Security

Is port 635 dangerous?

We have no specific security note for port 635. Its risk depends on the program actually listening on it. General advice for databases & caches services:

  • Bind the service to localhost or a private network, never to a public address.
  • Enable authentication, use per-application accounts and require TLS.
  • Watch for exposed Docker ports: publish them on 127.0.0.1 only.
02 Registry

IANA registry entries for port 635

ServicePortTransportDescriptionReferenceUpdated
rlzdbase 635 TCP, UDP RLZ DBase - -

// source: IANA service name and port number registry

03 Check it

Which program uses port 635, and is it reachable?

Linux

sudo ss -ltnup 'sport = :635'      # process listening on 635
sudo lsof -nP -i :635

macOS

sudo lsof -nP -i :635

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 635 -State Listen | Select LocalAddress, OwningProcess
Get-NetUDPEndpoint -LocalPort 635
netstat -ano | findstr :635

From another machine

nmap -p 635 -sV <host>
sudo nmap -sU -p 635 <host>
nc -zv <host> 635

Block it in the firewall

sudo ufw deny 635/tcp                                         # Linux (ufw)
New-NetFirewallRule -DisplayName "Block 635" -Direction Inbound -LocalPort 635 -Protocol TCP -Action Block  # Windows
04 FAQ
What is port 635 used for?

Port 635 is assigned by IANA to rlzdbase (RLZ DBase).

Is port 635 TCP or UDP?

Port 635 is registered for TCP and UDP.

Is it safe to open port 635?

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. Bind the service to localhost or a private network, never to a public address.

How do I check if port 635 is open?

On Linux run "ss -ltnup 'sport = :635'", on macOS "lsof -nP -i :635", and on Windows "netstat -ano | findstr :635" to see the local process. From another machine, "nmap -p 635 <host>" shows whether it is reachable.

05 Related
:3306 MySQL / MariaDB tcp · udp · high risk :1433 Microsoft SQL Server tcp · udp · high risk :5432 PostgreSQL tcp · udp · high risk :6379 Redis tcp · critical risk :27017 MongoDB tcp · critical risk :9200 Elasticsearch tcp · udp · critical risk :1521 Oracle Database tcp · udp · high risk :11211 Memcached tcp · udp · high risk

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