- 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.
Port 400: Oracle Secure Backup
Port 400 is assigned by IANA to osb-sd (Oracle Secure Backup).
400
How osb-sd works
Databases & cachesThe application sends a SQL query to the osb-sd server on port 400, 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
Is port 400 dangerous?
We have no specific security note for port 400. Its risk depends on the program actually listening on it. General advice for databases & caches services:
IANA registry entries for port 400
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| osb-sd | 400 | TCP, UDP | Oracle Secure Backup | - | 2023-12-27 |
// source: IANA service name and port number registry
Which program uses port 400, and is it reachable?
Linux
sudo ss -ltnup 'sport = :400' # process listening on 400
sudo lsof -nP -i :400macOS
sudo lsof -nP -i :400
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 400 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 400 netstat -ano | findstr :400
From another machine
nmap -p 400 -sV <host> sudo nmap -sU -p 400 <host> nc -zv <host> 400
Block it in the firewall
sudo ufw deny 400/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 400" -Direction Inbound -LocalPort 400 -Protocol TCP -Action Block # Windows
What is port 400 used for?
Port 400 is assigned by IANA to osb-sd (Oracle Secure Backup).
Is port 400 TCP or UDP?
Port 400 is registered for TCP and UDP.
Is it safe to open port 400?
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 400 is open?
On Linux run "ss -ltnup 'sport = :400'", on macOS "lsof -nP -i :400", and on Windows "netstat -ano | findstr :400" to see the local process. From another machine, "nmap -p 400 <host>" shows whether it is reachable.
Other databases & caches ports
: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