LinuxSoftware

Coding and tramping in Aotearoa / New Zealand

http://fedoranews.org/contributors/derek_pienaar/ddns http://ops.ietf.org/dns/dynupd/secure-ddns-howto.html http://www.wlug.org.nz/DHCPNotes are well worth reading.
(I plan to document my system at WLUGWiki soon too.)

DynamicDNS (DDNS) makes adding a new computer to my network as simple as plugging it into my switch. The new client tells the server what its host name is, and the server allocates it an address (DHCP) and lets the rest of the network know (DNS). No configuration at the server is required! (It's the next best thing to ZeroConf.) I like having this running as I was told it "couldn't be done" :-D.

The "secret key" is generated with dns-keygen.

/etc/named.conf 

// Dave's own hacked named.conf
// with dynamic DNS :-D

options {
        directory "/var/named";
        allow-query {
                192.168.10/24;
                192.168.12/24;
                localhost;
        };
//        forward only;
//        forward first;
        forwarders {
                210.55.24.14;
                210.55.24.8;
        };

};

//
controls {
        inet 127.0.0.1 allow { localhost; } keys { rndckey; };
};

// Master DNS servers
zone "." IN {
        type hint;
        file "named.ca";
};

// Localhost addresses
zone "localhost" IN {
        type master;
        file "localhost.zone";
        allow-update { none; };
};
zone "0.0.127.in-addr.arpa" IN {
        type master;
        file "named.local";
        allow-update { none; };
};

// Magic key which lets DHCP update DNS
key "DHCP-UPDATER" {
        algorithm       hmac-md5;
        secret "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff";
};

// Home network
zone "invermay" {
        type master;
        notify no;
        file "invermay.zone";
        allow-update { key DHCP-UPDATER; };
};

// Reverse name resolution for home network
zone "12.168.192.in-addr.arpa" {
        type master;
        notify no;
        file "named.invermay";
        allow-update { key DHCP-UPDATER; };
};

// Reverse name resolution for wireless link
zone "10.168.192.in-addr.arpa" {
        type master;
        notify no;
        file "named.invermay.decknet";
        allow-update { key DHCP-UPDATER; };
};

include "/etc/rndc.key";

/etc/dhcpd.conf 

# Dave's own hacked dhcpd.conf
# with dynamic DNS :-D

# Don't forget command line options are in /etc/sysconfig/dhcpd

ddns-domainname "invermay";
ddns-update-style interim;
#ignore client-updates;
#ddns-updates off;

# Magic key which lets DHCP update DNS
key "DHCP-UPDATER" {
        algorithm       hmac-md5;
        secret "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff";
};

# DNS zones to update
zone invermay. {
        primary 127.0.0.1;
        key DHCP-UPDATER;
}
zone 12.168.192.in-addr.arpa. {
        primary 192.168.12.254;
        key DHCP-UPDATER;
}
zone 10.168.192.in-addr.arpa. {
        primary 192.168.10.254;
        key DHCP-UPDATER;
}

# Home network on eth2
subnet 192.168.12.0 netmask 255.255.255.0 {
        # Default gateway
        option routers                  192.168.12.254;
        option subnet-mask              255.255.255.0;

        option domain-name              "invermay";
        option domain-name-servers      192.168.12.254;

        range           192.168.12.128  192.168.12.254;
        default-lease-time              86400;   # 1 day
        max-lease-time                  259200;  # 3 days

        authoritative;
        ddns-updates on;
}

# Wireless link on eth0
subnet 192.168.10.0 netmask 255.255.255.0 {
        # Default gateway
        option routers                  192.168.10.254;
        option subnet-mask              255.255.255.0;

        option domain-name              "invermay";
        option domain-name-servers      192.168.10.254;

        range           192.168.10.128  192.168.10.254;
        default-lease-time              86400;   # 1 day
        max-lease-time                  259200;  # 3 days

        authoritative;
        ddns-updates on;
}

/var/named/invermay.zone 

$ORIGIN .
$TTL 604800     ; 1 week
invermay                IN SOA  rata.invermay. root.rata.invermay. (
                                107        ; serial
                                28800      ; refresh (8 hours)
                                14400      ; retry (4 hours)
                                3024000    ; expire (5 weeks)
                                86400      ; minimum (1 day)
                                )
                        NS      rata.invermay.
$ORIGIN invermay.
$TTL 129600     ; 1 day 12 hours
feijoa                  A       192.168.10.253
                        TXT     "3128380ff01e7006b0688a5d32bba2d551"
$TTL 604800     ; 1 week
localhost               A       127.0.0.1
ollienet                A       192.168.12.254
rata                    A       192.168.12.254
tuxnet                  A       192.168.12.254

/var/named/localhost.zone 

$TTL    86400
$ORIGIN localhost.
@                       1D IN SOA       @ root (
                                        42              ; serial (d. adams)
                                        3H              ; refresh
                                        15M             ; retry
                                        1W              ; expiry
                                        1D )            ; minimum

                        1D IN NS        @
                        1D IN A         127.0.0.1

/var/named/named.invermay 

$ORIGIN .
$TTL 604800     ; 1 week
12.168.192.in-addr.arpa IN SOA  rata.invermay. root.rata.invermay. (
                                104        ; serial
                                28800      ; refresh (8 hours)
                                14400      ; retry (4 hours)
                                3024000    ; expire (5 weeks)
                                86400      ; minimum (1 day)
                                )
                        NS      rata.invermay.
$ORIGIN 12.168.192.in-addr.arpa.
254                     PTR     rata.invermay.

/var/named/named/named.invermay.decknet 

$ORIGIN .
$TTL 86400      ; 1 day
10.168.192.in-addr.arpa IN SOA  rata.invermay. root.rata.invermay. (
                                101        ; serial
                                28800      ; refresh (8 hours)
                                14400      ; retry (4 hours)
                                3024000    ; expire (5 weeks)
                                86400      ; minimum (1 day)
                                )
                        NS      rata.invermay.
$ORIGIN 10.168.192.in-addr.arpa.
$TTL 129600     ; 1 day 12 hours
253                     PTR     feijoa.invermay.
$TTL 86400      ; 1 day
254                     PTR     rata.invermay.

/var/named/named.local 

$TTL    86400
@       IN      SOA     localhost. root.localhost.  (
                                      1997022700 ; Serial
                                      28800      ; Refresh
                                      14400      ; Retry
                                      3600000    ; Expire
                                      86400 )    ; Minimum
              IN      NS      localhost.

1       IN      PTR     localhost.

Arghhh!!!! 

// just listen internally
        listen-on {
                192.168.10/24;
                192.168.12/24;
        };

Seemed like a good idea, but screwed up dynamic updating for some reason. Kept getting connection refused messages. And I'd changed a few things so it took me all day to figure out.

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