Figure 3-2 DHCP message format Table 3-2 Fields in a DHCP message Field Length Description op 1 byte Operation Code: indicates the general type of message. The values are: 1: DHCP Discover message 2: DHCP Offer message htype 1 byte Hardware Type: indicates the type of hardw...
Message Name Description DHCP DISCOVER A DHCP Discover message is broadcast by a DHCP client to locate a DHCP server when the client attempts to connect to a network for the first time. DHCP OFFER A DHCP Offer message is sent by a DHCP server to respond to a DHCP Discover message. ...
2. Each DHCP server offers configuration parameters such as an IP address to the client in a DHCP-OFFER message. The sending mode of the DHCP-OFFER is determined by the flag field in the DHCP-DISCOVER message. For more information, see "DHCP message format." 3. If the client receives mu...
Boot Filename: Optionally used by a client to request a particular type of boot file in a DHCPDISCOVER message. Used by a server in a DHCPOFFER to fully specify a boot file directory path and filename. This field may also be used to carry DHCP options, using the “option overload” ...
1、 DHCP snooping 端口分为trust(信任)接或untrust(非信任)两种安全级别 2、 trust接口上收到的来自DHCPserver的报文(如DHCPDISCOVER, DHCPOFFER, DHCPQEQUEST, DHCPACK)才会被放行; 3、 untrust接口上收到的来自DHCPserver的报文将被过滤掉(如DHCPOFFER,DHCPACK)...
客户端以广播方式发送DHCP-DISCOVER报文。 (2) 提供阶段,即DHCP服务器提供IP地址的阶段。DHCP服务器接收到客户端的DHCP-DISCOVER报文后,根据IP地址分配的优先次序选出一个IP地址,与其他参数一起通过DHCP-OFFER报文发送给客户端。 (3) 选择阶段,即DHCP客户端选择IP地址的阶段。如果有多台DHCP服务器向该客户端发来...
DHCP客户端在启动时发送广播包(DHCP Discover),请求 DHCP 服务器提供配置信息。 DHCP 服务器收到广播包后,从可用的 IP 地址池中为客户端分配一个 IP 地址,并将该信息封装在广播包中返回(DHCP Offer)。 客户端收到 DHCP Offer 后,会给服务器回复一个请求确认(DHCP Request),表示选择该提供的配置信息。
The formal request for the offered IP address (the DHCPREQUEST message) that is sent by the client is broadcast so that all other DHCP servers that received the DHCPDISCOVER broadcast message from the client can reclaim the IP addresses that they offered to the client. ...
Server host name not given Boot file name not given Magic cookie: DHCPOption: (53) DHCP Message Type (Discover)Length: 1 DHCP: Discover (1) Option: (57) Maximum DHCP Message Size Length: 2 Maximum DHCP Message Size: 1152 Option: (61) Client identifier Length:...
(Discover) Message type: Boot Request (1) Hardware type: Ethernet (0x01) Hardware address length: 6 Hops: 0 Transaction ID: 0x86b6eaaa Seconds elapsed: 1 Bootp flags: 0x0000 (Unicast) 0... ... ... ... = Broadcast flag: Unicast .000 0000 0000 0000 = Reserved flags: 0x0000 Clien...