Help required in modifying a CRON script 1

[ChrisRChamberlain]

Hi all

Have a cron script running every 15 minutes that updates the servers at

http://www.zoneedit.com

with current public Dynamic IP address.

The CRONTAB command line is

*/15 * * * * /var/www/zoneedit.sh

The content of /var/

http://www/zoneedit.sh

is typically

wget -O - --http-user=MyName --http-passwd=Password '[URL unfurl="true"]http://dynamic.zoneedit.com/auth/dynamic.html?host=www.mysite.net'[/URL]
wget -O - --http-user=MyName --http-passwd=Password '[URL unfurl="true"]http://dynamic.zoneedit.com/auth/dynamic.html?host=mysite.net'[/URL]

As can be seen, there is no checking of the public IP address to see if any changes have been made. So unless there has been a change, executing the code in /var/

http://www/zoneedit.sh

is a waste of time and resources.

So in pseudo code, the script would resemble this:-

If file /var/

http://www/ipaddress

does not exist, get the public IP address, save it to /var/

http://www/ipaddress

and execute the two wgets. (This is for the first time the script runs only.)

If file /var/

http://www/ipaddress

does exist, get the public IP address and save it to a variable. Compare the the content of /var/

http://www/ipaddress

to the variable.

If the same, do nothing.

If not the same, save the variable to /var/

http://www/ipaddress

and execute the two wgets.

Using this script means the linux server could check the public IP address more frequently than every 15 minutes, and, in theory, would appear to be a more efficient way of updating the servers at

http://www.zoneedit.com.

In thread54-1632489, Noway2 provided the necessary code to save the public IP address to both variable and file.

Would appreciate it if someone could fill in the gaps as outlned above.

TIA

FAQ184-2483​

Chris
PDFcommander.com
motrac.co.uk

 

[feherke]

Hi

More exactly you want to write yet another dynamic DNS client, as described in zoneedit.com's FAQ at "What are the specs of the dynamic update request?" ?

[gray]#!/bin/bash[/gray]

[navy]ipfile[/navy][teal]=[/teal][green][i]'/var/www/ipaddress'[/i][/green]

[teal][[[/teal] -f [green][i]"$ipfile"[/i][/green] [teal]]][/teal] [teal]&&[/teal] [navy]ipold[/navy][teal]=[/teal][green][i]"$(< "[/i][/green][navy]$ipfile[/navy][green][i]" )"[/i][/green]
[navy]ipnew[/navy][teal]=[/teal][green][i]"$( wget -q -O - checkip.dyndns.org | sed -e 's/.*Current IP Address: //;s/<.*$//' )"[/i][/green]

[b]if[/b] [teal][[[/teal] [green][i]"$ipold"[/i][/green] [teal]!=[/teal] [green][i]"$ipnew"[/i][/green] [teal]]];[/teal] [b]then[/b]
  echo [green][i]"$ipnew"[/i][/green] [teal]>[/teal] [green][i]"$ipfile"[/i][/green]
  wget -O - --http-user[teal]=[/teal]MyName --http-passwd[teal]=[/teal]Password [green][i]'[URL unfurl="true"]http://dynamic.zoneedit.com/auth/dynamic.html?host=www.mysite.net'[/URL][/i][/green]
  wget -O - --http-user[teal]=[/teal]MyName --http-passwd[teal]=[/teal]Password [green][i]'[URL unfurl="true"]http://dynamic.zoneedit.com/auth/dynamic.html?host=mysite.net'[/URL][/i][/green]
fi

Feherke.

http://free.rootshell.be/~feherke/

 

[ChrisRChamberlain]

Feherke

Many thanks for your post.

Yes, it is another dynamic DNS client, but one that would appear to use less resources than the script posted or ddclient, neither of which check for change in the public IP address.

The other advantage being the frequency of running the script. As I understand it, updating zoneedit too often would not be 'welcomed' by the zoneedit servers.

FAQ184-2483​

Chris
PDFcommander.com
motrac.co.uk