Why are there many ip connection error?

[WQ]

hi, we saw a lot ip connection errors, but firewall rule is "allow", and most of the traffics can pass through. Can anyone please advise why there are so many "ip connection error"? Thanks in advance!

[hjezzapaula]

Hi,

probably due to https://community.fortinet.com/t5/FortiGate/Technical-Tip-ip-conn-traffic-action-in-logs/ta-p/198452...

The value 'ip-conn' in the log field description means that traffic was allowed, but the session closed as the FortiGate did not receive any reply packet. The resulting error shows as 'IP connection error'.

This can occur if the connection to the remote server fails or a timeout occurs.

Packet losses may be experienced due to a bad connection, traffic congestion, or high memory and CPU utilization on either FortiGate or the host.

[WQ]

hi @hjezzapaula , thanks for your advice. However, I did continuous ping to the server from other network, not packet loss. The server is directly connected to the firewall DMZ, and the firewall load is very low now. The server is also at installation stage, not roll out to production yet. Why there are so many ip connection error? what is the default tcp timeout value of fortigate? pls advise, thanks in advance. 

[smaruvala]

Hi,

For which type of traffic you are observing the error? Are you seeing ip-conn error for UDP/DNS traffic or ping traffic or TCP traffic?

default session timeout is 3600 seconds. But if the session is not established and it is half open state then timers will be different. You can run the below command to see half-open timers.

FGVM # config sys global
FGVM (global) # show full-configuration | grep tcp-

Regards,

Shiva

[pavankr5]

Hello @WQ ,
The session closed because the FortiGate did not receive any reply packet. This is recorded as an 'IP connection error'. Here are several possible causes and troubleshooting steps:

Possible Causes
Remote Server Issues: The connection to the remote server might have failed, or there was a timeout.
Packet Loss: Network issues such as bad connections, traffic congestion, or high memory and CPU utilization on either the FortiGate or the host could cause packet loss.
ICMP Errors: If an ICMP error message is sent by a client or server, it can trigger this error. For example, a client using the same source port for consecutive queries might cause an ICMP 'Destination unreachable (Port unreachable)' error.
We need to collect logs to examine it further.
 https://community.fortinet.com/t5/FortiGate/Technical-Tip-ip-conn-traffic-action-in-logs/ta-p/198452...

Thanks,
Pavan