blocks|key|248759|text|是个广播。发现，提供，请求，ACK都是广播的。在整个过程完成之前，客户端不会获得IP地址。所以它必须广播。您可以看到更多的这里。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|248760|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_request^0|1P|2|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

It's a broadcast. DISCOVER, OFFER, REQUEST, ACK are all broadcast. Client does not get an IP address before the whole process is completed. So it has to broadcast. You can see more <a href="https://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_request" rel="nofollow noreferrer">here</a>.

blocks|key|248183|text|DHCPOFFER和DHCPACK通常作为单播从服务器发送到客户端。客户端可以设置广播标志，请求服务器将广播发送回客户端，但这不是首选方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|248184|这在https://www.rfc-editor.org/rfc/rfc2131#section-4.1中有详细说明。|offset|length|248185|对于使用DHCP进行初始配置的客户端(在客户端的TCP/IP软件完全配置之前)，DHCP需要创造性地使用客户端的TCP/IP软件，并对RFC+1122进行自由解释。在配置IP地址之前，TCP/IP软件应接受并转发到客户端硬件地址的任何IP数据包；DHCP服务器和BOOTP中继代理可能无法在配置TCP/IP软件之前将DHCP消息传递给无法接受硬件单播数据报的客户端。
为了处理某些客户端在配置TCP/IP软件之前不能接受IP单播数据报的问题，DHCP使用了“标志”字段21。最左边的位被定义为广播(B)标志。本文档第4.1节讨论了此标志的语义。标志字段的其余部分保留给以后使用。客户端必须将它们设置为零，服务器和中继代理必须忽略它们。图2给出了“标志”字段的格式。
1+1+1%2B-B:广播标志MBZ:必须为零(留待将来使用)图2：“标志”字段的格式|blockquote|248186|-而且--|248187|通常，DHCP服务器和BOOTP中继代理试图使用uicast传递直接将DHCPOFFER、DHCPACK和DHCPNAK消息传递给客户端。IP目标地址(在IP报头中)设置为DHCP+'yiaddr‘地址，链路层目标地址设置为DHCP+'chaddr’地址。不幸的是，一些客户端实现无法接收这样的单播IP数据报，直到实现配置了有效的IP地址(导致在客户端配置了IP地址之前无法传递客户端IP地址的死锁)。|248188|entityMap|0|LINK|mutability|MUTABLE|url|https://www.rfc-editor.org/rfc/rfc2131#section-4.1^0|0|2|1E|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|H|7|Z|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|10|8|@]|9|@]|A|$]]|$1|K|3|L|5|H|7|11|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

The DHCPOFFER and DHCPACK are normally sent from the server to the client as unicast. The client can set a Broadcast flag to request that the server send broadcast back to the client, but this is not the preferred method.
This is detailed in <a href="https://www.rfc-editor.org/rfc/rfc2131#section-4.1" rel="nofollow noreferrer">RFC 2131, Dynamic Host Configuration Protocol</a>:
<blockquote>
In the case of a client using DHCP for initial configuration (before
the client's TCP/IP software has been completely configured), DHCP
requires creative use of the client's TCP/IP software and liberal
interpretation of RFC 1122. The TCP/IP software SHOULD accept and
forward to the IP layer any IP packets delivered to the client's
hardware address before the IP address is configured; DHCP servers and
BOOTP relay agents may not be able to deliver DHCP messages to clients
that cannot accept hardware unicast datagrams before the TCP/IP
software is configured.
To work around some clients that cannot accept IP unicast datagrams
before the TCP/IP software is configured as discussed in the previous
paragraph, DHCP uses the 'flags' field [21]. The leftmost bit is
defined as the BROADCAST (B) flag. The semantics of this flag are
discussed in section 4.1 of this document. The remaining bits of the
flags field are reserved for future use. They MUST be set to zero by
clients and ignored by servers and relay agents. Figure 2 gives the
format of the 'flags' field.
<pre><code> 1 1 1 1 1 1
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |B| MBZ |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 B: BROADCAST flag

 MBZ: MUST BE ZERO (reserved for future use)

 Figure 2: Format of the 'flags' field
</code></pre>
</blockquote>
-and-
<blockquote>
Normally, DHCP servers and BOOTP relay agents attempt to deliver
DHCPOFFER, DHCPACK and DHCPNAK messages directly to the client using
uicast delivery. The IP destination address (in the IP header) is set
to the DHCP 'yiaddr' address and the link-layer destination address is
set to the DHCP 'chaddr' address. Unfortunately, some client
implementations are unable to receive such unicast IP datagrams until
the implementation has been configured with a valid IP address
(leading to a deadlock in which the client's IP address cannot be
delivered until the client has been configured with an IP address).
</blockquote>

blocks|key|870222|text|客户机和服务器之间的DHCP消息交换可以根据DHCP消息中字段的设置进行广播或单播，特别是广播标志字段、客户端IP地址(ciaddr)字段和网关IP地址(Giaddr)字段。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|870223|以下是简要说明细目：|870224|*如果设置了广播标志字段，则服务器将向客户端广播&+ACK，但前提是客户端和服务器位于同一广播域中。|870225|*如果网关IP地址(Giaddr)字段为非零，则在client和Server之间存在中继代理，因此所有服务器消息都是单播到中继代理IP地址。|870226|*如果客户端IP地址(Ciaddr)字段为非零，服务器将向该客户端IP地址提供&+ACK。|870227|*如果未设置广播位，客户端IP地址字段为零，网关IP地址字段为零，服务器将将DHCP消息单播到客户端硬件地址(chaddr)。|870228|*如果服务器标识符IP地址(+siaddr+)字段为非零，客户端将向siaddr中的该IP地址发送所有消息。此字段将是非零提供和ACK消息，因为DHCP服务器将设置它来标识它自己。|870229|https://www.niledigitech.com/447/dynamic-host-configuration-protocol/|offset|length|870230|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|0|0|0|0|0|1X|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|12|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|13|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|14|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|15|8|@]|9|@$P|16|Q|17|1|18]]|A|$]]|$1|R|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|S|$T|$5|U|V|W|A|$X|O]]]]

Exchange of DHCP message between client and server can either be broadcast or unicast depending on setting of the fields inside in DHCP message in particular, broadcast flags field, client IP address (ciaddr) field and gateway IP address(giaddr) field.

Below is a summary note breakdown

*If broadcast flag field is set, the server will broadcast OFFER &amp; ACK to client but only if client &amp; server are in the same broadcast domain.

*If gateway IP address(giaddr) field is non-zero, there is relay agent between client &amp; Server, therefore all server message are unicast to relay agent IP address.

*If client IP address(ciaddr) field is non-zero, server will unicast OFFER &amp; ACK to that client IP address

*If broadcast bit is not set, client IP address field is zero and gateway IP address field is zero, server will unicast DHCP message to client hardware address (chaddr)

*If server identifier IP address(siaddr) field is non-zero, client will send all message to that IP address in siaddr. This field will be non-zero in OFFER and ACK message because DHCP server will set it to identify it self.

<a href="https://www.niledigitech.com/447/dynamic-host-configuration-protocol/" rel="nofollow noreferrer">https://www.niledigitech.com/447/dynamic-host-configuration-protocol/</a>

DHCP process occurs in 4 stages as DORA. I know Discover and Offer are broadcast. Is DHCP request message a broadcast or Unicast?

Is DHCP request message a broadcast or Unicast?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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DHCP过程分为4个阶段，即DORA。我知道“发现”和“提供”是广播的。DHCP请求消息是广播还是单播？

问DHCP请求消息是广播还是单播？
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问DHCP请求消息是广播还是单播？
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