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3.13 DHCP server configuration
Dynamic Host Configuration Protocol (DHCP) can be used for automatically assigning IP addresses and other information to the
So be sure to have your server in a separate network, or use statical IP configuration for all nodes and servers that you do not want to serve. Clients usually take the first address offer they get, and often it is the wrong one. Example 3-25. /etc/dhcpd.conf
not authoritative;
ddns-update-style ad-hoc;
default-lease-time 60000;
max-lease-time 720000;
option myoption code 129 = text ;
# dynamically assigned adress range
# every client can get one
subnet 192.168.100.0 netmask 255.255.255.0 {
range 192.168.100.211 192.168.100.212;
option routers 192.168.100.60;
option nameservers 192.168.100.110;
option domain residency.local;
# statically assigned adresses, only clients
# with designated MAC adress will get it
group {
next-server 192.168.100.110;
host lpar1 {
fixed-address 192.168.100.77;
hardware ethernet 00:02:55:3A:06:8C;
filename "install";
}
host lpar2 {
fixed-address 192.168.100.78;
hardware ethernet 00:02:55:6f:1f:e3;
filename "yaboot";
option root-path "/tftpboot/";
}
host lpar3 {
fixed-address 192.168.100.79;
hardware ethernet 00:02:55:3a:06:19;
filename "yaboot";
}
}
}
After editing /etc/dhcpd.conf, we start our dhcpd server: # /etc/init.d/dhcpd start Check /var/log/messages: Example 3-26. /ect/var/log/messages excerpt:.... dhcpd: Internet Software Consortium DHCP Server V3.0.1rc9 Oct 22 15:40:50 p630sles dhcpd: Copyright 1995-2001 Internet Software Consortium. Oct 22 15:40:50 p630sles dhcpd: All rights reserved. Oct 22 15:40:50 p630sles dhcpd: For info, please visit http://www.isc.org/products/DHCP Oct 22 15:40:50 p630sles dhcpd: Wrote 0 deleted host decls to leases file. Oct 22 15:40:50 p630sles dhcpd: Wrote 0 new dynamic host decls to leases file. Oct 22 15:40:50 p630sles dhcpd: Wrote 0 leases to leases file. Oct 22 15:40:50 p630sles dhcpd: Listening on LPF/eth0/00:02:55:4f:60:8a/CSM Oct 22 15:40:50 p630sles dhcpd: Sending on LPF/eth0/00:02:55:4f:60:8a/CSM Oct 22 15:40:50 p630sles dhcpd: Sending on Socket/fallback/fallback-net .... If you have left the dynamically assigned address range in the dhcpd.conf file, then every client configured to be a dhcpd client will get an address from this range. For network installations or network boot, we strongly recommend that you use statically assigned addresses in order to prevent installing servers or clients you do not intend. |
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3.14 DNS server configuration
As a starting point we use the default caching only nameserver configuration provided by SuSE. The caching only
In order to use local name resolution too, we add two new zone records: residency.local (name to IP address), and 100.168.192.rev for reverse name resolution (IP address to name). For debugging, we add the logging section because it forces the name server daemon to log all requests in /var/log/messages. [18]
Example 3-27. /etc/named.conf
options {
directory "/var/named";
forwarders {
9.12.6.7;
};
listen-on { any;};
notify no;
forward first;
};
zone "localhost" in {
type master;
file "localhost.zone";
};
zone "0.0.127.in-addr.arpa" in {
type master;
file "127.0.0.zone";
};
zone "." in {
type hint;
file "root.hint";
};
# You can insert further zone records for your own domains below.
logging {
category queries {
default_syslog;
};
category update {
default_syslog;
};
};
zone "residency.local" {
type master;
file "/var/named/residency.local.hosts";
};
zone "100.168.192.in-addr.arpa" {
type master;
file "/var/named/100.168.192.rev";
};
Now we create our own local zone files: residency.local, and for reverse lookup, 100.168.192.rev. We need a residency.local file in order to be able to resolve names to IP addresses. Example 3-28. /var/named/residency.local
$ttl 38400 residency.local. IN SOA 192.168.100.110. root.p630sles. (
0310221736 ; serial
10800 ; refresh
3600 ; retry
604800 ; expiry
38400 ) ; minimum
residency.local. IN NS 192.168.100.81
$GENERATE 111-254 node-$ A 192.168.100.$
lpar8.residency.local. IN A 192.168.100.84
lpar7.residency.local. IN A 192.168.100.83
lpar6.residency.local. IN A 192.168.100.82
lpar5.residency.local. IN A 192.168.100.81
lpar4.residency.local. IN A 192.168.100.80
lpar3.residency.local. IN A 192.168.100.79
lpar2.residency.local. IN A 192.168.100.78
lpar1.residency.local. IN A 192.168.100.77
p630sles.residency.local. IN A 192.168.100.110
Important Every time you change something in the zone file, you need to change the serial number in the second line.
In order to resolve addresses to names, we need a file for reverse name resolution. In this file, addresses are written in
Example 3-29. /var/named/100.168.192.rev
$ttl 38400100.168.192.in-addr.arpa. IN SOA p630sles. root.p630sles. (
9998899999
10800
3600
604800
38400 )
100.168.192.in-addr.arpa. IN NS p630sles
77.100.168.192.in-addr.arpa. IN PTR lpar1.
78.100.168.192.in-addr.arpa. IN PTR lpar2.
79.100.168.192.in-addr.arpa. IN PTR lpar3.
80.100.168.192.in-addr.arpa. IN PTR lpar4.
81.100.168.192.in-addr.arpa. IN PTR lpar5.
82.100.168.192.in-addr.arpa. IN PTR lpar6.
83.100.168.192.in-addr.arpa. IN PTR lpar7.
84.100.168.192.in-addr.arpa. IN PTR lpar8.
110.100.168.192.in-addr.arpa. IN PTR p630sles.
$GENERATE 111-254 $ PTR node-$
.
Tip The trick in both zone files is in the line starting with $GENERATE: it will assign all nodes above 111 names; that is, node-111, node-112 and so on. This is a useful feature in combination with a dhcpd server for a larger environment or cluster, because you do not need to add nodes one by one anymore. |
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