Question about ISC-dhcp, subnet and options
Ulf Zimmermann
ulf at openlane.com
Tue Oct 30 00:52:37 UTC 2012
I have a question about options inside of subnet definations. Part of my config is below:
# VLAN 52 - 10.1.1.0/24
subnet 10.1.1.0 netmask 255.255.255.0 {
authoritative;
option routers 10.1.1.1;
option subnet-mask 255.255.255.0;
option domain-name "example.com";
option domain-name-servers 10.2.0.5, 10.2.0.6;
option netbios-name-servers 10.3.0.71, 10.3.0.72;
option time-offset -28800; # Pacific Standard Time
option ntp-servers 10.3.0.69, 10.4.0.40;
# PXE Kickstart section to be included from file
include "/etc/dhcp/includes.fremont/kickstart-10.1.1.0-24.conf";
}
# VLAN 2 - Network Management 10.3.0.0/22
subnet 10.3.0.0 netmask 255.255.252.0 {
authoritative;
option routers 10.3.0.1;
option subnet-mask 255.255.252.0;
option domain-name "example.com";
option domain-name-servers 10.2.0.5, 10.2.0.6;
option netbios-name-servers 10.3.0.71, 10.3.0.72;
option time-offset -28800; # Pacific Standard Time
option ntp-servers 10.3.0.69, 10.4.0.40;
default-lease-time 21600; # 6 hours
max-lease-time 43200; # 12 hours
class "pxeclients" {
match if substring(option vendor-class-identifier, 0, 9) = "PXEClient";
next-server 10.3.0.12;
filename "pxelinux.0";
#if not exists gpxe.bus-id {
# filename "/gpxelinux.0";
#}
}
# Kickstart config file for 10.3.0.0/22
include "/etc/dhcp/includes.fremont/kickstart-10.3.0.0-22.conf";
# Static IP assignments via DHCP
include "/etc/dhcp/includes.fremont/static-10.3.0.0-22.conf";
# Include the iLO config file for 10.137.8.0/22
include "/etc/dhcp/includes.fremont/ilo-10.3.0.0-22.conf";
}
# VLAN 10 - Corporate - 10.5.0.0/22
subnet 10.5.0.0 netmask 255.255.252.0 {
authoritative;
option routers 10.5.0.1;
option subnet-mask 255.255.252.0;
option domain-name "example.com";
option domain-name-servers 10.2.0.5, 10.2.0.6;
option netbios-name-servers 10.3.0.71, 10.3.0.72;
option time-offset -28800; # Pacific Standard Time
option ntp-servers 10.3.0.69, 10.4.0.40;
default-lease-time 21600; # 6 hours
max-lease-time 43200; # 12 hours
# Kickstart config file for 10.5.0.0/22
include "/etc/dhcp/includes.fremont/kickstart-10.5.0.0-22.conf";
# Static IP assignments via DHCP
include "/etc/dhcp/includes.fremont/static-10.5.0.0-22.conf";
}
The problem I am running into is that on the VLAN 52 I am getting the following response from dhcpd:
10:47:24.273532 IP (tos 0x0, ttl 63, id 60694, offset 0, flags [none], proto UDP (17), length 576)
10.8.0.165.bootps > 10.3.0.21.bootps: BOOTP/DHCP, Request from 00:50:56:aa:46:c5, length 548, hops 1, xid 0x57aa46c5, secs 4, Flags [Broadcast]
Gateway-IP 10.1.1.1
Client-Ethernet-Address 00:50:56:aa:46:c5
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Parameter-Request Option 55, length 24:
Subnet-Mask, Time-Zone, Default-Gateway, IEN-Name-Server
Domain-Name-Server, RL, Hostname, BS
Domain-Name, SS, RP, EP
Vendor-Option, Server-ID, Vendor-Class, BF
Option 128, Option 129, Option 130, Option 131
Option 132, Option 133, Option 134, Option 135
MSZ Option 57, length 2: 1260
GUID Option 97, length 17: 0.66.42.10.5.180.105.222.121.213.164.28.115.149.149.224.89
ARCH Option 93, length 2: 0
NDI Option 94, length 3: 1.2.1
Vendor-Class Option 60, length 32: "PXEClient:Arch:00000:UNDI:002001"
10:47:24.273997 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 328)
10.3.0.21.bootps > 10.1.1.1.bootps: BOOTP/DHCP, Reply, length 300, hops 1, xid 0x57aa46c5, secs 4, Flags [Broadcast]
Your-IP 10.1.1.30
Server-IP 10.3.0.155
Gateway-IP 10.1.1.1
Client-Ethernet-Address 00:50:56:aa:46:c5
file "/rhel6server-x86_64/pxelinux.0"
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Server-ID Option 54, length 4: 10.3.0.21
Lease-Time Option 51, length 4: 21600
Subnet-Mask Option 1, length 4: 255.255.252.0
Time-Zone Option 2, length 4: -28800
Default-Gateway Option 3, length 4: 10.3.0.1
Domain-Name-Server Option 6, length 8: 10.2.0.5,10.2.0.6
Domain-Name Option 15, length 8: "autc.com"
The problematic parts are:
Subnet-Mask Option 1, length 4: 255.255.252.0
Default-Gateway Option 3, length 4: 10.3.0.1
Shouldn't this return 255.255.255.0 and 10.1.1.1 based on the above subnet declaration? Should the "options routers" and "options subnet-mask" be local to the subnet declaration?
Ulf.
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