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Date:      Thu, 8 Jul 2004 14:51:04 -0600
From:      Tillman Hodgson <tillman@seekingfire.com>
To:        FreeBSD-Questions <freebsd-questions@freebsd.org>
Subject:   dhclient.conf and DDNS via TSIG to Bind 9.2.3
Message-ID:  <20040708205104.GE37443@seekingfire.com>

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Howdy,

I have a backup connection on an ADSL line with an IP address provided
by DHCP. My main line, which has static IPs, hosts my Bind 9.2.3 DNS
server. I don't have control of the DHCP server for the backup line,
it's simply provided by the ISP.

I'm using dhclient from -CURRENT on i386, dated June 17 2004.

I'd like to have dhclient on the backup line update a DNS entry in one
of my zones so that I can always reach my network via the backup line at
the same name. I'm following
http://ops.ietf.org/dns/dynupd/secure-ddns-howto.html as well as a
similar thread from the freebsd hackers lsit from last November:
http://groups.google.ca/groups?hl=en&lr=&ie=UTF-8&th=86443cc1d80de8da&rnum=2

I set up the named.conf on the DNS host as follows (IPs aren't mangled
... they're dyanmic, after all :-)):

key "adsl.seekingfire.com." {
	algorithm hmac-md5;
	secret "<my secret generated from dnssec-keygen>";
};
view "us" {
	match-clients { MyNets; };
	// Master zones
	zone "seekingfire.com" {
		type master;
		file "master/seekingfire.com";
		allow-transfer { MyNets; AccessComm; };
		// for dynamic DNS
		allow-update { key adsl.seekingfire.com.; };
		// Note: I've also tried:
		//update-policy {
		//      grant adsl.seekingfire.com. name
		//      adsl.seekingfire.com. A TXT;
		//};
	};

And I've set up dhclient.conf as follows:

### Keys and DDNS (see
http://ops.ietf.org/dns/dynupd/secure-ddns-howto.html)
send fqdn.fqdn "adsl.seekingfire.com.";
send fqdn.encoded on;
send fqdn.server-update off;
key adsl.seekingfire.com. {
        algorithm HMAC-MD5;
        secret <my secret generated from dnssec-keygen>";
}
zone seekingfire.com {
        key adsl.seekingfire.com.;
}
interface "xl0" {
        send dhcp-client-identifier "adsl";
        send host-name "adsl";
}

When I add "dhclient_flags="-v"" to /etc/rc.conf and run
/etc/rc.d/dhclient restart, I get:

Releasing DHCP leases: xl0.
Starting dhclient.
Internet Software Consortium DHCP Client V3.0.1rc12
Copyright 1995-2002 Internet Software Consortium.
All rights reserved.
For info, please visit http://www.isc.org/products/DHCP
Listening on BPF/xl0/00:01:02:2d:17:47
Sending on   BPF/xl0/00:01:02:2d:17:47
Sending on   Socket/fallback
DHCPDISCOVER on xl0 to 255.255.255.255 port 67 interval 6
DHCPOFFER from 64.110.241.254
DHCPREQUEST on xl0 to 255.255.255.255 port 67
DHCPACK from 64.110.241.254
bound to 142.165.192.118 -- renewal in 6982 seconds.
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=9<RXCSUM,VLAN_MTU>
        inet6 fe80::201:2ff:fe2d:1747%xl0 prefixlen 64 scopeid 0x2
        inet 142.165.192.118 netmask 0xffffff00 broadcast 142.165.192.255
        ether 00:01:02:2d:17:47
        media: Ethernet 10baseT/UTP (10baseT/UTP <half-duplex>)
        status: active

So, yeah, I get my new lease just fine. But it doesn't mention anything
about DNS ... and when I run a tcpdump on the adsl host, I don't see any
traffic on port 53. It's like it's just ignoring that part of
dhclient.conf completely.

Is there something I missing or have messed up in my dhclient.conf
configuration?

-T


-- 
Page 12: Unix is a set of tools for smart people.
	- Harley Hahn, _The Unix Companion_



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