호리의 IT 기록장: 4월 2016

환경
Base OS CentOS 7
DHCP version 4.2.5
IP 192.168.17.210
GATEWAY 192.168.17.2
Hostname sungsik.mirhenge.com
root계정으로 진행

선행작업
1. 먼저 IP할당을 static으로 바꿔놓는다. (설정법은 나중에 설명)

2. NetworkManager를 끄고 부팅시 off 상태로 만든다.
#systemctl stop NetworkManager
#systemctl disable NetworkManager

3. Virtual Machine Settings에 들어가 Network Adapter부분에
Custom:specific virtual network 체크한 후 VMnet8(NAT) 로 설정한다

4. vmware workstation의 Edit->Virtual Network Editor->Change Settings->예->
VMnet8 클릭-> Use local DHCP service to distribute IP address to VMs 체크해제
->상단 VMnet8 부분에 DHCP가 - 된것을 확인후 OK누른다

DHCP Server 설치 및 설정

DHCP package 가 설치되었는지 확인
# rpm -qa | grep dhcp
dhcp-common-4.2.5-42.el7.centos.x86_64 // 기본으로
dhcp-libs-4.2.5-42.el7.centos.x86_64 // 2가지가 보일 것이다.

DHCP package 설치
#yum -y install dhcp
패키지가 설치 될 것임 complete가 뜰 때까지 기달린다

DHCP package 설치확인
#rpm -qa | grep dhcp
dhcp-4.2.5-42.el7.centos.x86_64
dhcp-common-4.2.5-42.el7.centos.x86_64
dhcp-libs-4.2.5-42.el7.centos.x86_64

DHCP 예비설정 파일을 올바른 경로로 옮긴다
#cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf

/etc/dhcp에 dhcpd.conf가 제대로 옮겼는지 확인
#ls /etc/dhcp
dhclient.d dhcpd6.conf dhcpd.conf ->바로 이파일!!
//dhcpd.conf파일은 DHCP server가 host들에게 할당하는 IP범위 지정,DNS로 지정할 //domain name과 domain name server
//(domain name -> sungsik domain name server -> sungsik.mirhenge.com)
//최소 IP할당 시간,최대 IP 할당 시간 등 DHCP서버의 동작을 설정하는 파일이다

dhcpd.conf파일을 연다
#vi /etc/dhcp/dhcpd.conf
# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#

# option definitions common to all supported networks...
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;

default-lease-time 600;
max-lease-time 7200;

# Use this to enble / disable dynamic dns updates globally.
#ddns-update-style none;

......... (넘 기니까 중간 생략....
........... 이런 환경으로 하고 싶으면 이것만 설정하고 저런 환경으로 하고 싶으면 저것만
........... 설정해라 라는 예시이다. 중간에 #이 아닌 부분이 있는데 수정하지 말고 내비둔다 아무 문제 발생안함.)

shared-network 224-29 {
subnet 10.17.224.0 netmask 255.255.255.0 {
option routers rtr-224.example.org;
}
subnet 10.0.29.0 netmask 255.255.255.0 {
option routers rtr-29.example.org;
}
pool {
allow members of "foo";
range 10.17.224.10 10.17.224.250;
}
pool {
deny members of "foo";
range 10.0.29.10 10.0.29.230;
}

}

dhcpd.conf파일 수정(파란색 부분 = 수정 검붉은 부분 = 추가)

# Sample configuration file for ISC dhcpd

# option definitions common to all supported networks...

option domain-name "mirhenge.com";

option domain-name-servers sungsik.mirhenge.com;

default-lease-time 600;

max-lease-time 7200;

authoritative;

subnet 192.168.17.0 netmask 255.255.255.0{

option routers 192.168.17.1; -> ex) 자신의 IP주소가

option subnet-mask 255.255.255.0; 192.168.39.145 이런 형식이면은 router는
192.168.39.1

option domain-search "mirhenge.com"; 145 -> 1 로바꾼다

option domain-name-servers 192.168.17.210; ->도메인서버의 ip를 쓰면 된다.

option broadcast-address 192.168.17.255; ex) 자신의 IP주소가 192.168.39.145 이런 주소면 broadcast주소는 192.168.39.255

option time-offset -18000; 즉 145->255

range 192.168.17.212 192.168.17.220; -> 임의로 IP할당 범위를 min 에서 max 까지 지
} 정해줌 본인은 212~220 까지 범위를 준 것

host station1{ ->특정 컴퓨터에게 고정IP를 넣어주는 부분

option host-name "station1.example.com";

hardware ethernet 00:0c:29:69:bc:77; -> 특정 컴퓨터의 맥주소 넣는다

fixed-address 192.168.17.220; -> range 범위에서 가장 끝 ip주소를 넣는다

}

// 이 뒤에 나오는 복잡한 영어는 안 건드려도 된다 #이 안붙은 것도 무시 가능!!
(단 지우진 마세요)

# Use this to enble / disable dynamic dns updates globally.

#ddns-update-style none;

# If this DHCP server is the official DHCP server for the local

# network, the authoritative directive should be uncommented.

#authoritative;

# Use this to send dhcp log messages to a different log file (you also

# have to hack syslog.conf to complete the redirection).

log-facility local7;

# No service will be given on this subnet, but declaring it helps the

# DHCP server to understand the network topology.

subnet 10.152.187.0 netmask 255.255.255.0 {

}

# This is a very basic subnet declaration.

subnet 10.254.239.0 netmask 255.255.255.224 {

range 10.254.239.10 10.254.239.20;

option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;

}

# This declaration allows BOOTP clients to get dynamic addresses,

# which we don't really recommend.

subnet 10.254.239.32 netmask 255.255.255.224 {

range dynamic-bootp 10.254.239.40 10.254.239.60;

option broadcast-address 10.254.239.31;

option routers rtr-239-32-1.example.org;

}

# A slightly different configuration for an internal subnet.

subnet 10.5.5.0 netmask 255.255.255.224 {

range 10.5.5.26 10.5.5.30;

option domain-name-servers ns1.internal.example.org;

option domain-name "internal.example.org";

option routers 10.5.5.1;

option broadcast-address 10.5.5.31;

default-lease-time 600;

max-lease-time 7200;

}

# Hosts which require special configuration options can be listed in

# host statements. If no address is specified, the address will be

# allocated dynamically (if possible), but the host-specific information

# will still come from the host declaration.

host passacaglia {

hardware ethernet 0:0:c0:5d:bd:95;

filename "vmunix.passacaglia";

server-name "toccata.fugue.com";

}

# Fixed IP addresses can also be specified for hosts. These addresses

# should not also be listed as being available for dynamic assignment.

# Hosts for which fixed IP addresses have been specified can boot using

# BOOTP or DHCP. Hosts for which no fixed address is specified can only

# be booted with DHCP, unless there is an address range on the subnet

# to which a BOOTP client is connected which has the dynamic-bootp flag

# set.

host fantasia {

hardware ethernet 08:00:07:26:c0:a5;

fixed-address fantasia.fugue.com;

}

# You can declare a class of clients and then do address allocation

# based on that. The example below shows a case where all clients

# in a certain class get addresses on the 10.17.224/24 subnet, and all

# other clients get addresses on the 10.0.29/24 subnet.

class "foo" {

match if substring (option vendor-class-identifier, 0, 4) = "SUNW";

}

shared-network 224-29 {

subnet 10.17.224.0 netmask 255.255.255.0 {

option routers rtr-224.example.org;

}

subnet 10.0.29.0 netmask 255.255.255.0 {

option routers rtr-29.example.org;

}

pool {

allow members of "foo";

range 10.17.224.10 10.17.224.250;

}

pool {

deny members of "foo";

range 10.0.29.10 10.0.29.230;

}

수정한 dhcpd.conf 저장 후 닫는다.

아시죠? esc 누르고 :wq

Network 재시작
#service network restart

DHCP서비스를 시작한다

#systemctl start dhcpd

● dhcpd.service - DHCPv4 Server Daemon

Loaded: loaded (/usr/lib/systemd/system/dhcpd.service; enabled; vendor preset: disabled)

Active: active (running) since Thu 2016-04-07 22:53:17 PDT; 28s ago

Docs: man:dhcpd(8)

man:dhcpd.conf(5)

Main PID: 7985 (dhcpd)

Status: "Dispatching packets..."

CGroup: /system.slice/dhcpd.service

└─7985 /usr/sbin/dhcpd -f -cf /etc/dhcp/dhcpd.conf -user dhcpd -group dhcpd --no-pid

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: No subnet declaration for virbr0 (192.168.122.1).

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: ** Ignoring requests on virbr0. If this is not what

Apr 07 22:53:17 sungsik.mirhengser.com dhcpd[7985]: you want, please write a subnet declaration

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: in your dhcpd.conf file for the network segment

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: to which interface virbr0 is attached. **

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]:

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: Listening on LPF/eno16777736/00:0c:29:69:bc:77/192.168.17.0/24

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: Sending on LPF/eno16777736/00:0c:29:69:bc:77/192.168.17.0/24

Apr 07 22:53:17 sungsik.mirhenge.com dhcpd[7985]: Sending on Socket/fallback/fallback-net

Apr 07 22:53:17 sungsik.mirhenge.com systemd[1]: Started DHCPv4 Server Daemon.

DHCP서비스를 부팅시 자동온 설정한다

#systemctl enable dhcpd

Created symlink from /etc/systemd/system/multi-user.target.wants/dhcpd.service to /usr/lib/systemd/system/dhcpd.service.

네트워크 재시작

#service network restart

Restarting network (via systemctl): [ OK ]

DHCP Client 설정

기본적으로 CentOS 7은 DHCP Client가 깔려있음

Virtual Machine Settings에 들어가 Network Adapter부분에
Custom:specific virtual network 체크한 후 VMnet8(NAT) 로 설정한다

vmware NetworkManager 종료와 부팅시 off 설정
#systemctl stop NetworkManager
#systemctl disable NetworkManager

/etc/sysconfig/network-scripts로 경로이동
#cd /etc/sysconfig/network-scripts

ls로 이더넷 장치 확인
#ls
ifcfg-eno16777736 ifdown-ppp ifup-ib ifup-Team
ifcfg-lo ifdown-routes ifup-ippp ifup-TeamPort
ifdown ifdown-sit ifup-ipv6 ifup-tunnel
ifdown-bnep ifdown-Team ifup-isdn ifup-wireless
ifdown-eth ifdown-TeamPort ifup-plip init.ipv6-global
ifdown-ib ifdown-tunnel ifup-plusb network-functions
ifdown-ippp ifup ifup-post network-functions-ipv6
ifdown-ipv6 ifup-aliases ifup-ppp
ifdown-isdn ifup-bnep ifup-routes

ifdown-post ifup-eth ifup-sit
필자는 eno16777736으로 잡혀있음 아마 대부분은 eth0이나 eth1일 것임

ifcfg-eno16777736수정
#vi ifcfg-eno16777736
TYPE=Ethernet
BOOTPROTO=dhcp
DEVICE=eno16777736
ONBOOT=yes
NAME=eno16777736
GATEWAY=192.168.17.2
NETMASK=255.255.255.0
DNS=8.8.8.8
// 요런식으로 수정해준다.

network를 재시작한다
#service network restart
Restarting network (via systemctl): [ OK ]

ip a 명령어로 DHCP Server에서 dhcpd.conf 파일에 설정한 range 부분에 설정한 범위에
맞게 ethernet 장치에 IP 가 들어갔는지 확인한다. (필자는 192.168.17.211~192.168.17.220)
#ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:e8:1f:cb brd ff:ff:ff:ff:ff:ff
inet 192.168.17.212/24 brd 192.168.17.255 scope global dynamic eno16777736
valid_lft 378sec preferred_lft 378sec
inet6 fe80::20c:29ff:fee8:1fcb/64 scope link
valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN
link/ether 52:54:00:db:d5:bd brd ff:ff:ff:ff:ff:ff
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 500
link/ether 52:54:00:db:d5:bd brd ff:ff:ff:ff:ff:ff

ping을 통해 제대로 패킷을 주고 받는지 확인한다
#ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=128 time=76.0 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=128 time=80.8 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=128 time=78.0 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=128 time=74.4 ms
64 bytes from 8.8.8.8: icmp_seq=5 ttl=128 time=95.2 ms
64 bytes from 8.8.8.8: icmp_seq=6 ttl=128 time=81.9 ms
^C
--- 8.8.8.8 ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5018ms
rtt min/avg/max/mdev = 74.481/81.094/95.282/6.844 ms

// 핑 테스트 종료는 Ctrl+c

여기까지 제대로 되었다면 DHCP Server 구축 및 운영에 성공한 것

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