Troubleshooting
Problem
Some devices or applications running on them might fail, for one reason or another, to maintain an established TCP session with QRadar collector host and might drop and reconnect multiple times due to an underlying networking issue. Another common cause is a client (device) side corporate firewall, configured to time out idle TCP connections. However, if you notice the behavior for many of the devices connected to the same collector, you should probably investigate the collector side as well.
Symptom
In such cases on the QRadar collector side, Max TCP Syslog Connections Per Host (by default 10) value is reached because the old stale sessions are not properly closed on the sending device side. This problem is usually due to firewall timing out idle sessions, and it is not configured to send an RST (reset) packet on that action.
We can then observe on the collector host up to 10 stale connections and in /var/log/qradar.error we see errors similar to:
We can then observe on the collector host up to 10 stale connections and in /var/log/qradar.error we see errors similar to:
[ecs-ec-ingress.ecs-ec-ingress] [TcpSyslog(0.0.0.0/514) Protocol Provider Thread: class com.q1labs.semsources.sources.tcpsyslog.TcpSyslogProvider0] com.q1labs.semsources.sources.tcpsyslog.TcpSyslogProvider: [WARN] [NOT:0000004000][10.10.10.20/- -] [-/- -]connectionsPerHost[10] maximum [10] reached for host [IP ADDRESS] ... dropping connection
The device is no longer accepted to establish a new connection on TCP port 514, so events are not transmitted beyond that point.
In rare cases a device might use more than one active session for sending Syslog traffic, so if there is any suspicion that it might be the case, you need to check the device configuration and its documentation.
In rare cases a device might use more than one active session for sending Syslog traffic, so if there is any suspicion that it might be the case, you need to check the device configuration and its documentation.
Document Location
Worldwide
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Document Information
Modified date:
07 December 2022
UID
ibm16838625