DNS Names for PPTP

mschulz · Mon Apr 20, 2009 2:12 pm

Hi All,

i run a MT Router that must permanently connect as PPTP client to a private PPTP Server. This private server changes every day its public IP adress due to the ISP. So I made a dynDNS account for it.

The problem is, that the PPTP client "connect-to" only accepts plain IP adresse and no DNS Names. So the client disconnects every time the server changes its IP address and i have to set the new connection IP for the client manually.

Is there a workarround for this problem?

Thanks alot, Marco.

NAB · Mon Apr 20, 2009 2:20 pm

I'll second that request - I have exactly the same problem with NTP.

We use the ntp.org pool service, so I'd like to set primary and secondary NTP to:

0.uk.pool.ntp.org
1.uk.pool.ntp.org

However, I can't!

Nick.

Mon Apr 20, 2009 2:29 pm

run scheduled script that is resolving ip address and tehen comparing it with currently set ntp or pptp address. If it is not the same replace it.

NAB · Mon Apr 20, 2009 3:43 pm

OK. First time at a script more than one line long! Seems to work, but can somebody sanity check this?

:local ntpaip [:resolve "0.uk.pool.ntp.org"];
:local ntpbip [:resolve "1.uk.pool.ntp.org"];

:local ntpcura [/system ntp client get primary-ntp];
:local ntpcurb [/system ntp client get secondary-ntp];

:if ($ntpaip != $ntpcura) do={
    /system ntp client set primary-ntp="$ntpaip";
    }

:if ($ntpbip != $ntpcurb) do={
    /system ntp client set secondary-ntp="$ntpbip";
    }

My main concern is that I usually do all sorts of paranoid checks on values, but after having read the scripting documentation, I can't see how to:

1 - Make a log entry if either of the ':resolve' commands fail.
2 - Check that what's returned is reasonably valid (simple regex to exclude known invalid addresses - e.g. 0.0.0.0, 127.0.0.0/8, 192.168.0.0/16 etc.)
3 - Probably some other things somebody else will pick up on!

So, what do you think?

Mon Apr 20, 2009 4:00 pm

Your script looks good.

1- script will stop instantly if :resolve fails, so it is not possible to write log if it fails. In v4.0 it will be fixed
2- v3.23 has new operator '~' that does exactly what you need
http://wiki.mikrotik.com/wiki/Scripting#Other_Operators

NAB · Mon Apr 20, 2009 6:08 pm

Since I've just got the e-mail to say 3.23 is available, I'd better try it!

hilton · Mon Apr 20, 2009 6:54 pm

Since I've just got the e-mail to say 3.23 is available, I'd better try it!

Great stuff, let us know please.

NAB · Wed Apr 22, 2009 2:11 pm

Not got as far as using Regexes, but I've put the NTP pool script up on http://wiki.mikrotik.com/wiki/Scripting-examples

Nick.

hilton · Wed Apr 22, 2009 2:50 pm

thanks for this Nick. Good stuff.

DNS Names for PPTP

DNS Names for PPTP

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