Port 904VMware Server Alternate Port
Port 904 serves as an alternate communication channel for VMware components when the default port 902 is unavailable, often on certain Linux distributions such as SUSE. It facilitates management connections for ESXi hosts, vCenter Server, and remote console services, playing a critical role in the VMware virtualization ecosystem by enabling secure and efficient management traffic flow..
- transport
- tcp
- in transit
- cleartext
- assignment
- unofficial
- risk
- 4/10
- lookups
- 7,403
single transport
payload readable on path
used by convention
caution
rank 687 of 993 · top 69%
Technical Details
what runs on :904Port 904 is used as an alternative to VMware's default port 902 to facilitate management and remote console connections to ESXi hosts and other VMware infrastructure components. This occurs primarily in circumstances where port 902 is occupied or blocked due to system-specific configurations like on some SUSE Linux distributions.
When active, port 904 handles communication between the VMware Client, such as the vSphere Client or other management utilities, and VMware ESXi hosts. This includes remote console operations, file transfers, authentication sequences, and communication with VMware agents residing on the hosts. Its presence helps maintain management continuity, particularly in complex environments with diverse deployment scenarios.
The port is typically enabled by VMware services such as the hostd management agent and the vpxa (vCenter Agent). Since it is not the primary port, it is often dynamically activated based on network conditions or administrative configuration, ensuring operational flexibility within VMware's virtualization framework.
Security Information
exposure of :904risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
network services averages 3.9 across 604 ports — this one sits 0.1 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
unofficial
used by convention, not registered — what answers here varies by deployment
reachable over
tcp
every listening transport is another surface to filter at the edge
security overview
Common vulnerabilities on port 904 arise due to improper access controls and unencrypted communication, exposing management interfaces to potential exploitation, including unauthorized access, privilege escalation, and data interception by attackers. If this port is improperly exposed to public or untrusted internal networks, attackers might gain footholds that allow manipulation of host systems or virtual machines.
Mitigations include:
- Restricting port 904 access using strong ACLs and host-based firewalls
- Enabling VPN or encrypted tunnels for management traffic where possible
- Regularly patching VMware components to address known vulnerabilities
- Implementing strong authentication controls
- Monitoring and alerting for unusual activity targeting VMware ports
Securing this port significantly reduces attack surface for VMware management planes, limiting the risk of compromise.
Related Ports
the 8 most looked-up other ports in network services — 604 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :9080 | Groove RPC | TCPUDP | Web Services | caution | 70.8k |
| :6543 | Jetnet | UDP | Network Services | caution | 65.3k |
| :5938 | TeamViewer | TCPUDP | Remote Access | caution | 65.0k |
| :8291 | Winbox MikroTik Admin | TCP | Security | caution | 62.9k |
| :3233 | WhiskerControl Protocol | TCPUDP | Network Services | caution | 61.9k |
| :3268 | Microsoft Global Catalog (GC) | TCPUDP | Security | caution | 54.6k |
| :135 | Microsoft EPMAP | TCPUDP | Security | caution | 51.9k |
| :3128 | Tatsoft Default HTTP Proxy | TCP | Web Services | caution | 46.8k |
risk mix of the 8 listed
- caution100%
0 of 8 encrypted