Why does Privoxy constantly listen 1087 port after updating macOS?

Question

Environment

macOS - 10.15.4 (19E266)

V2rayU - 2.1.0

Description

After updating macOS to 10.15.4, when I try to turn V2ray on, it says

http error - listen tcp 127.0.0.1:1087: bind: address already in use

With lsof -i :1087, I find that it is privoxy listening 1087 port. However, even I try privoxy kill it or restart, it will still appear soon and continue using 1087.

There is no similar circumstance before system update, I used to use 1087 for V2ray.

Expectation

V2ray run successfully on 1087.

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(Although change the port to another is a possible solution, it is still a strange thing for privoxy itself running in the system)

Answer 1

1087 is a system and network alarm logging service. It is an IANA registered port.

Well Known Ports: 0 through 1023. 
Registered Ports: 1024 through 49151. 
Dynamic/Private : 49152 through 65535

Answer 2

The kernel_task thread will use port 1087. lsof -i:1087 and use kill PID, and this process cannot be terminated.

I was troubled by this problem for a long time, and finally I found out that I was using ITunes to backup my IPhone data Will occupy port 1087, and finally wait for the backup to end, successfully solve the problem.