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이론 관련/네트워크 관련2026. 3. 13. 16:36

DHCP option

예전에 찾아봤던 신기한 녀석의 후속글.. 이라고 해야하나?

0~255 총 256개의 옵션이 존재하며 BOOTP 에서 유래하거나 DHCP에서 추가된 것들이 있는 것 같은데..

dhcp 서버 설정을 해본적이 없는것 같네.. dhcpd.conf 뒤져보면 나오려나?

RFC 1497 (BOOTP Vendor Information Extensions) vendor extensions[13]: Section 3 CodeNameLengthNotes

0	Pad	0 octets	Can be used to pad other options so that they are aligned to the word boundary; is not followed by length byte
1	Subnet mask	4 octets	Client's subnet mask as per RFC 950. If both the subnet mask and the router option (option 3) are included, the subnet mask option must be first.
2	Time offset	4 octets	Time offset of the client's subnet in seconds from Coordinated Universal Time (UTC). The offset is expressed as a two's complement 32-bit integer. A positive offset indicates a location east of the zero meridian and a negative offset indicates a location west of the zero meridian.
3	Router	Multiples of 4 octets	Available routers, should be listed in order of preference
4	Time server	Multiples of 4 octets	Available Time Protocol servers to synchronise with, should be listed in order of preference
5	Name server	Multiples of 4 octets	Available IEN 116 name servers, should be listed in order of preference
6	Domain name server	Multiples of 4 octets	Available DNS servers, should be listed in order of preference
7	Log server	Multiples of 4 octets	Available log servers, should be listed in order of preference
8	Cookie server	Multiples of 4 octets	Cookie in this case means "fortune cookie" or "quote of the day", a pithy or humorous anecdote often sent as part of a logon process on large computers; it has nothing to do with cookies sent by websites.
9	LPR Server	Multiples of 4 octets	A list of Line Printer Daemon protocol servers available to the client, should be listed in order of preference
10	Impress server	Multiples of 4 octets	A list of Imagen Impress servers available to the client, should be listed in order of preference
11	Resource location server	Multiples of 4 octets	A list of Resource Location Protocol servers available to the client, should be listed in order of preference
12	Host name	Minimum of 1 octet	Name of the client. The name may be qualified with the local domain name.
13	Boot file size	2 octets	Length of the boot image in 512B blocks
14	Merit dump file	Minimum of 1 octet	Path where crash dumps should be stored
15	Domain name	Minimum of 1 octet
16	Swap server	4 octets	The IP address of a server where a swap service (e.g., swap over NFS) is provided for diskless workstations[14]
17	Root path	Minimum of 1 octet	The path in the remote filesystem specified by siaddr or sname that the client should mount as its root filesystem (e.g, over NFS)
18	Extensions path	Minimum of 1 octet
255	End	0 octets	Used to mark the end of the vendor option field

[링크 : https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#Options]

This appendix contains DHCP options and BOOTP vendor extensions from RFC 2132, and includes the
validation type for each option, as indicated in Table 10: DHCPv4 Options by Number , on page 23.

The following sections describe the DHCP options in detail:
• RFC 1497 Vendor Extensions, on page 1

[링크 : https://www.cisco.com/c/en/us/td/docs/net_mgmt/prime/network_registrar/10-0/dhcp/guide/DHCP_Guide/DHCP_Guide_appendix_01101.pdf]

DHCP option 43 / 25DHCP (Dynamic Host Configuration Protocol) 에는 클라이언트가 DHCP 서버로부터 정보를 요청할 때 클라이언트에게 송신할 수 있는 많은 구성 옵션이 있습니다. 검색 도구를 사용하여 모든 DHCP 옵션을 볼 수 있습니다.

DHCP 옵션은 DHCP 서버가 IP 주소와 함께 클라이언트에게 전달하는 추가적인 구성 데이터를 정의합니다. 일반적인 옵션에는 서브네트 마스크, 도메인명, 라우터 IP 주소, 도메인명 서버 IP 주소 및 정적 라우트가 포함됩니다.

RFC 2132: DHCP 옵션 및 BOOTP 공급업체 확장의 정의를 기반으로 하는 표준 DHCP 옵션이 다음 표에 설명되어 있습니다. IBM Navigator FOR I의 DHCP 옵션 표시를 사용하여 사용자 지정 옵션을 구성할 수도 있습니다.

[링크 : https://www.ibm.com/docs/ko/i/7.5.0?topic=concepts-dhcp-options-lookup]

[링크 : http://www.ktword.co.kr/test/view/view.php?no=1925]

윈도우 서버 DHCP 설정

[링크 : https://undefinedmaster.tistory.com/23] 43

linux dhcpd 설정

host x41  {
hardware ethernet 00:0a:e4:2f:66:38;
fixed-address 10.0.0.201;
option subnet-mask 255.255.255.0;
option domain-name-servers 10.0.0.20;
option domain-name "site";
  option vendor-class-identifier "PXEClient";
  vendor-option-space PXE;
    option PXE.discovery-control 7;
    option PXE.boot-server 15 1 10.0.0.20;
    option PXE.boot-menu 15  15 "Tpm for OSd 7.1";
    option PXE.menu-prompt 0 "Tpm for Osd";
}

[링크 : https://www.ibm.com/docs/en/tpmfod/7.1.1.14?topic=configuration-dhcpdconf-example]

[링크 : https://manpages.ubuntu.com/manpages/bionic/man5/dhcp-options.5.html]

[링크 : https://y7712.tistory.com/entry/Ubuntu-DHCP]

dhcp 옵션에서 1번이 subnet 3번이 router 인데 아래 옵션이 그 옵션인가?

default-lease-time 600;
max-lease-time 7200;
subnet 10.0.0.0 netmask 255.255.255.0 {
option subnet-mask 255.255.255.0;
option routers 10.0.0.1;
range 10.0.0.5 10.0.0.15;
}
subnet 172.16.0.0 netmask 255.255.255.0 {
option subnet-mask 255.255.255.0;
option routers 172.16.0.1;
range 172.16.0.5 172.16.0.15;
}

[링크 : https://docs.redhat.com/ko/documentation/red_hat_enterprise_linux/7/html/networking_guide/sec-configuring_a_multihomed_dhcp_server]