Time synchronization on the Touch and PW

[bhaak]

I noticed a funny thing about how the Kindle Touch and Paperwhite do their time synchronization.

The system calls the shell script /usr/sbin/updatetime (identical on the Touch and the PW).

This script first calls a NTP server at Amazon configured in /etc/sysconfig/ntp.

So far, nothing special. Using NTP is standard procedure.

If the script can't reach the NTP server it falls back on making a web request to an Amazon web server, filtering out the date header from the web server's response.

Nice idea for those situation where only http requests into the net are allowed.

In my case this doesn't help as I have blocked any access out of my intranet on my Touch so I changed the address to a local web server. But then I noticed that the web request is not completely standard compliant (the line endings are wrong) and because of that there was no response.

I changed the get_web_time() function and then it worked flawlessly:

get_web_time()
{
    printf "HEAD / HTTP/1.0\r\n\r\n" | nc ${HTTP_SERVER} 80 | grep "Date: " | cut -d ' ' -f 3-
}

[sitrucz]

I tried modifying the code as suggested and updated the ntp server to time.nist.gov without success. I don’t have a local web server to sync. Does anyone have any other ideas to get time sync working on a wifi only Paperwhite?

[knc1]

Originally Posted by sitrucz

I tried modifying the code as suggested and updated the ntp server to time.nist.gov without success. I don’t have a local web server to sync. Does anyone have any other ideas to get time sync working on a wifi only Paperwhite?

run the ntp server on your router. I do.

[aditya3098]

Not every router has ddwrt or openwrt

[mike.s]

Originally Posted by sitrucz

I tried modifying the code as suggested and updated the ntp server to time.nist.gov without success. I don’t have a local web server to sync. Does anyone have any other ideas to get time sync working on a wifi only Paperwhite?

"The code as suggested" was for getting time from a web server, not an ntp server. nist.time.gov is not a web server. You really shouldn't be configuring an end device to point to a stratum 1 ntp server, anyway.

Try changing /etc/sysconfig/ntp so it has a line like:

NTP_SERVER=0.pool.ntp.org

[sitrucz]

I checked my time capsule and it doesn't have an ntp server. I was hoping for a quick fix but I'm ok for the 30 seconds it takes to set the time manually if it slips. Thanks to all.

[knc1]

Originally Posted by aditya3098

Not every router has ddwrt or openwrt

But many of them do support a time sync service.

Also, the most commonly used TelCo aDSL modem used in the USA has a time sync service which may be optioned "on".
Even has a choice of protocols that it will support.

[bhaak]

Originally Posted by sitrucz

I tried modifying the code as suggested and updated the ntp server to time.nist.gov without success. I don’t have a local web server to sync. Does anyone have any other ideas to get time sync working on a wifi only Paperwhite?

When you start /usr/sbin/updatetime manually it will spit out some debug info.

Also before running for a test do 'rm /var/run/prntpset.dat'. The script caches in this file the last result and if not sufficient time has passed since the last run, it doesn nothing.

By default it only allows a check once a day. This is configured by the value of NTP_CHECK_TIME in /etc/sysconfig/ntp.