Date: Sun, 09 Dec 2001 10:02:24 -0600 From: jacks@sage-american.com To: freebsd-questions@freebsd.org Subject: Scripting help Message-ID: <3.0.5.32.20011209100224.0101cb38@mail.sage-american.com>
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I have just set up an experimental FBSD 4.4-STABLE server using DSL with
dynamic ip. Using ZoneEdit DNS services, the DNS can be updated with a cron
script to still point to the proper name. I'm doing that now using cron to
run the update script every 8 hours (the connection usually runs for weeks
at a time without disconnect).
However, I had rather have a script that runs every so often (xminutes) and
doesn't bother the DNS server unless and ONLY if a changed in the dynamic
IP has occured as a result of disconnect/reconnect. Here are the functions
I see needed, but scripting language is not yet a decent skill of mine. I
suspect others using dynamic IPs have this same need: Any guidence
appreciated once again. (I've looked at the ipcheck that uses Python, but
rather not go that route if possible to do the simple approach below).
BEGIN (my crude) SCRIPT:
#!/bin/sh
PATH=/usr/local/bin:/usr/bin:/bin
## This script would be run by cron every x_minutes
## (files needed: "last_known_ip" and "my_current_ip")
## Contents of last_known_ip (placed there manually at for first output
## by running ifconfig tun0 > last_known_ip
tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1492
inet 64.xxx.xx.20 --> 64.xxx.xx.254 netmask 0xffffffff
Opened by PID 149
## Run update to my_current_ip file
# function: ifconfig tun0 > my_current_ip
##.... so the "my_current_ip" file would contain output of:
tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1492
inet 64.xxx.xx.20 --> 64.xxx.xx.254 netmask 0xffffffff
Opened by PID 149
## Now make comparison to see if dynamic ip has changed and update DNS if
changed.
# function: look in my_current_ip and find the current ip (64.xxx.xx.20)
# function: look in last_known_ip file and find ip (64.xxx.xx.66)
# function: if not same, then run DNS_ping_program to update (ping command
here)
## If change detected, update comparison file
# function: ifconfig tun0 > last_known_ip
# function: if same ip, then do nothing
END OF SCRIPT
The above may be a crude approach, but best way I can define the job for
now....
Best regards,
Jack L. Stone,
Server Admin
Sage-American
http://www.sage-american.com
jacks@sage-american.com
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