Hi all
Some time ago my internet provider blocked external ntp requests. The problem is that their ntp server sucks. A couple of days ago I observed 15s drift, today about 7s. For some reason I'd like to have more reliable time.
Is there any way to achieve is? Any there any alternative solutions? Maybe something with tunelling? It doesn't need to be constant synchronisation. A sync script started 2-3 times a day would be probably enough. I'm developer so I'm able to write some helper program if it is necessary but I don't know how to obtain reliable time data.

Can You advise something?

Add an entry to crontab that runs ntpdate once an hour.

As I said they blocked ntp requests going outside, so ntpdate doesn't work.

If you install ntpd you can let it sync (to nanosecond accuracy, if required) to GPS time if you can see the sky and can afford a $25 GPS dongle.
Then you are your own source of the correct time. You could also broadcast it to others, if they request it and you have a little spare bandwidth.

If you want super-accuracy, you need a GPS dongle with a 1PPS output, and a (very) little hardware hacking (Eg. install a wire to make a connection from the GPS receiver to a GPIO pin on the Pi) might be needed.

I once had a Raspberry Pi in the attic syncing ntpd from a cheap GPS dongle. Only accurate to 1second, as I had no 1PPS signal. Fun project though.

Lots more info here:

http://www.catb.org/gpsd/gpsd-time-service-howto.html

Have fun, and maybe let us know how you get on.

Sounds good!
Fortunately I ordered my first Pi2 two days ago

Thanks!

Ntpdate uses another port when run from a regular user.

Isn't there some secure ntp that should not be easily blocked?

Wonder why they block ntp?

they claim it is due to some recent attacks (for me they seem not to be security experts - they just heard sth and are afraid):

https://en.wikipedia.org/wiki/Networ...urity_concerns