:dec/23/2021 19:41:52 phase1 negotiation failed due to time up 192.168.101.4[500]<=>134.209.114.23[39201] 2f0aab10fff24dc7:a6f720328aa2f8e7
Then the CPU usage rate increases.
I don’t know what ?
The message is related to IPsec processing. The IPsec session to your server (the public IP shown in the log, you may want to edit it out from the post and the topic title) fails to establish. So if you have configured bare IPsec, or something (L2TP, IPIP, EoIP, GRE) over IPsec, something fails during the process of establishing the session; if you haven’t, it must have either been a previous administrator or some malware.