UNI-FIX Computer

This is an example for a private /24 network prefixed width 10.10.10. With a dhcp area from 1-50 and server ip 254 and admin pc 100.

First dhcpd.conf:
option domain-name “lan.company.dk”;
option domain-name-servers 10.10.10.254;
default-lease-time 600;
max-lease-time 7200;
authoritative;
ddns-update-style interim;
ddns-ttl 7200;

subnet 10.10.10.0 netmask 255.255.255.0 {
range 10.10.10.1 10.10.10.50;
option routers 10.10.10.254;
option broadcast-address 10.10.10.255;
ignore client-updates;
ddns-updates on;
ddns-domainname “lan.”;
ddns-rev-domainname “in-addr.arpa.”;
default-lease-time 600;
max-lease-time 7200;

key “dhcpkey” {
algorithm hmac-md5;
secret
“secretmd5hashwhoknowsfor”;
};

zone cafe. {
primary 127.0.0.1;
key “dhcpkey”;
}

zone 10.10.10.in-addr.arpa {
primary 127.0.0.1;
key “dhcpkey”;
}

}

host admin {
hardware ethernet 00:0b:6a:46:31:77;
fixed-address 10.10.10.100;
}

– dhcpd.conf end

Next we need some dns. We need bind 9, the named.conf should look something like this:

include “/usr/local/etc/rndc.key”;

options {
directory “/usr/local/etc”;
pid-file “/var/run/named/pid”;
};

zone “cafe.” IN {
type master;
file “lan.zone”;
update-policy { grant dhcpkey subdomain lan. A TXT; };
notify yes;
};

zone “10.10.10.in-addr.arpa.” {
type master;
file “lan.rev”;
update-policy { grant dhcpkey subdomain 10.10.10.in-addr.arpa. PTR TXT; };
notify yes;
};

zone “.” {
type hint;
file “named.root”;
};

– named.conf end

Ofcourse path’s may change, this was done on freebsd, this one requires 2 zonefiles and a rndc.key:

key “dhcpkey” {
algorithm hmac-md5;
secret “secretmd5hashwhoknowsfor”;
};

– rndc.key end

Key’s are genereated and then cut’n’pasted:
localhost# dnssec-keygen -a HMAC-MD5 -b 256 -n HOST dhcpkey
Kdhcpkey.+157+00190
localhost# dnssec-keygen -a HMAC-MD5 -b 256 -n HOST dhcpkey
Kdhcpkey.+157+43984

lan.zone:
$TTL 10800 ; 3 hours
cafe IN SOA server.lan. ekim.at.unifix.org. (
115 ; serial
10800 ; refresh (3 hours)
3600 ; retry (1 hour)
604800 ; expire (1 week)
3600 ; minimum (1 hour)
)
NS server.lan.
A 10.0.0.1
admin A 10.10.10.100
main A 10.10.10.254
server A 10.10.10.254
lan.zone – end

and lan.rev:
$TTL 180 ; 3 minutes
10.10.10.in-addr.arpa IN SOA main.lan. mike.at.unifix.org. (
16 ; serial
180 ; refresh (3 minutes)
60 ; retry (1 minute)
60 ; expire (1 minute)
60 ; minimum (1 minute)
)
NS main.lan.
100 PTR admin.lan.
254 PTR server.lan.
lan.rev – end

Notice evntualle that .254 has both main and server as A record but can only have one PTR record thus server.lan.

Happy hacking, now your network should be namyfied 🙂

Maskiner som requester dhcp og angiver deres hostadresse kan der laves lookup paa med flg. script. Hvis ikke det virker er det hoejest sandsynligt fordi dit os kalder dhcpd paa en anden maade en min freebsd box goer(std opsat) saa kan du angive path til dhcpd.leases filen manuelt. Jeg har lagt filen i /bin og kaldt den ‘fip’ derved:

vbcafe# ssh `fip pc9`
ssh: connect to host 10.10.10.19 port 22: Connection refused

og her var scriptet:

#!/usr/bin/perl

open fil, “ps ax|”;
while ( $dat = <fil>)
{
if ($dat =~ /dhcpd/)
{
@dat = split(” “,$dat);
$path=@dat[8];
}
}

$saveip=”not found\n”;

# $path = ‘-set-to-dhcpd.leases-file-if-dosnt-work’;

open fil,$path;
while ($dat=<fil>)
{
chop(@dat);
@dat=split(” “,$dat);
if ( @dat[0] eq “lease”) { $ip=@dat[1]; }
if ( @dat[1] eq ‘”‘.$ARGV[0].'”;’) { $saveip=$ip; }
}
close(fil);

print $saveip;

if ($saveip eq “not found”) {exit -1;}

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Og til sidst 2 blanker linier til ære for Ove Sprogø, den store danske skuespiller som idag desvære ikke er mere. Må fred være med ham.

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