brain-dump/android/custom-time-server-lineageos.md

Setting a Custom Time Server on LineageOS / Custom ROM

I use AFWall and saw a lot of outgoing denied connections to a bunch of IPs when I wasn't using the phone, the outgoing connections route under "Linux Kernel," instead of a system app that may be making the call, so a bit of work is involved in figuring out who Android is trying to talk to.

One of them happened to be 216.239.35.12 - a whois 216.239.35.12 reports back it's owned by Google.

Does this IP have a nameserver that can clue me in on what it does?

nslookup 216.239.35.12

12.35.239.216.in-addr.arpa name = time4.google.com.

I'd rather deprive Google of that sliver of data of my device phoning in, so I want to change the NTP server (and then I will allow NTP to access the web!)

• Hook up the device to a laptop with ADB / Android Debug Bridge
• adb devices to activate a connection

Obtain the current NTP setting

adb shell settings get global ntp_server

• null = Google's choice

Set your own

adb shell settings put global ntp_server 0.pool.ntp.org

Check the setting, now

adb shell settings get global ntp_server

0.pool.ntp.org