How to set up dhcp_2_dns.sh

dhcp_2_dns.sh is a script which updates tinydns with addresses handed out by dhcpd. This is useful for Bering firewalls because DNS and DHCP will be synchronized.

Here’s how to set it up:

First, make sure tinydns is set up and running (directions are here).
Copy dhcp_2_dns.sh onto your firewall. I put my copy in /usr/bin/. Add /usr/bin/dhcp_2_dns.sh to /var/lib/lrpkg/tinydns.list:
```
...
usr/bin/tinydns-data
usr/bin/dhcp_2_dns.sh
etc/tinydns-private/
...
```
(This adds dhcp_2_dns.sh to the tinydns.lrp package).

Edit /etc/init.d/tinydns so that dhcp_2_dns.sh is run every time tinydns starts. Add the call near the end of set_dnscache():

...
    echo "" > /var/run/resetdns.pid
    /usr/bin/dhcp_2_dns.sh      # run dhcp_2_dns.sh
    RESET_DNS=Y
}
...

Back up tinydns.lrp
Edit /etc/multicron-p and add dhcp_2_dns.sh to periodic():
```
periodic () {
    checkfreespace
    pingcheck
    /usr/bin/dhcp_2_dns.sh
}
```
By default, periodic() is run every 15 minutes. This can be changed in /etc/cron.d/multicron.
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How to set up dhcp_2_dns.sh