- Keep directory and authentication services on internal networks.
- Require signing or TLS and disable anonymous queries.
- Monitor authentication failures for spraying and brute force.
Port 3868: DIAMETER
Port 3868 is assigned by IANA to diameter (DIAMETER).
3868
How diameter works
Directory & authenticationThe client proves who it is on port 3868 and gets an answer (or a ticket) it can use with other services.
- Transport
- TCP · SCTP
- 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
- Directory & authentication
Is port 3868 dangerous?
We have no specific security note for port 3868. Its risk depends on the program actually listening on it. General advice for directory & authentication services:
IANA registry entries for port 3868
| Service | Port | Transport | Description | Reference | Updated |
|---|---|---|---|---|---|
| diameter | 3868 | TCP, SCTP | DIAMETER | - | - |
| - | 3868 | - | Reserved | - | - |
// source: IANA service name and port number registry
Which program uses port 3868, and is it reachable?
Linux
sudo ss -ltnup 'sport = :3868' # process listening on 3868
sudo lsof -nP -i :3868macOS
sudo lsof -nP -i :3868
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3868 -State Listen | Select LocalAddress, OwningProcess Get-NetUDPEndpoint -LocalPort 3868 netstat -ano | findstr :3868
From another machine
nmap -p 3868 -sV <host> nc -zv <host> 3868
Block it in the firewall
sudo ufw deny 3868/tcp # Linux (ufw) New-NetFirewallRule -DisplayName "Block 3868" -Direction Inbound -LocalPort 3868 -Protocol TCP -Action Block # Windows
What is port 3868 used for?
Port 3868 is assigned by IANA to diameter (DIAMETER).
Is port 3868 TCP or UDP?
Port 3868 is registered for TCP and SCTP.
Is it safe to open port 3868?
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. Keep directory and authentication services on internal networks.
How do I check if port 3868 is open?
On Linux run "ss -ltnup 'sport = :3868'", on macOS "lsof -nP -i :3868", and on Windows "netstat -ano | findstr :3868" to see the local process. From another machine, "nmap -p 3868 <host>" shows whether it is reachable.
Other directory & authentication ports
:389 LDAP tcp · udp · high risk :636 LDAPS tcp · udp · moderate risk :88 Kerberos tcp · udp · high risk :3268 Global Catalog (LDAP) tcp · udp · high risk :1812 RADIUS udp · tcp · moderate risk :31 MSG Authentication tcp · udp :49 Login Host Protocol (TACACS) tcp · udp :56 XNS Authentication tcp · udp