A client reset in FortiGate refers to a situation where the client-side of a network session sends a reset packet to abruptly terminate the connection. This is indicated in FortiGate logs with the value 'client-rst' in the log description.
Understanding Client Resets
When a client sends a reset (RST) packet, it's essentially telling the server, "I'm closing this connection immediately, and don't expect any further communication." This can occur for various reasons, often indicating an issue on the client side.
Common Causes of Client Resets
- Application Errors: The client application might encounter an error that causes it to terminate the connection abruptly.
- User Actions: A user might close a browser tab, end an application, or power off their device, leading to a reset packet being sent.
- Network Issues: Although less common, intermittent network problems or conflicts on the client side can sometimes trigger a reset packet.
- Firewall or Security Software: Aggressive security software on the client can mistakenly terminate legitimate connections by sending a RST packet.
FortiGate Log Details
The FortiGate firewall logs can help you identify when a client reset occurs. When you see "client-rst" in the log description, it indicates that:
- The reset originated from the client device, not the server or the FortiGate itself.
- The connection was terminated without a proper close handshake.
Why Client Resets Matter
- Troubleshooting: Client resets can help pinpoint problems originating on the user's end.
- Security Analysis: In some cases, a large number of client resets might indicate unusual behavior requiring further investigation.
- Application Performance: Frequent resets could point to issues with client application stability.
Practical Implications
| Aspect | Details |
|---|---|
| Troubleshooting Scenarios | When a connection is unexpectedly terminated, check FortiGate logs to see if "client-rst" is present; if so, focus on client-side issues. |
| Frequency Analysis | Occasional client resets are normal, but frequent resets may suggest underlying issues that should be investigated. |
| Client Behavior | Client applications that frequently send reset packets might need software updates or configuration reviews. |
Examples of Situations
- A user closes their browser while a page is loading: the browser sends a reset packet.
- A mobile application crashes on the user's phone: the app sends a reset packet.
- Security software on a laptop blocks a suspicious connection: the software might send a reset.
In summary, a client reset, as indicated by "client-rst" in FortiGate logs, means the connection termination originated from the client. Understanding this helps in diagnosing and addressing network and application issues.
