DHCP的四个广播包的作用是什么？ DHCP offer 为什么不是广播包?
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你只要弄清楚DHCP原理.你的问题也就清楚了...DHCP工作俗话说“四次握手”没IP的客户机发送的第一个包是向全"世界"(网络）广播.作用是：在网络中寻找DHCP服务器.第二次广播包是所有收到客户端发的广播包的DHCP服务器回应客户端.并提供一个带有IP信息可用的广播包.第三次是客户端选择的机会..她会选择最快，最近回复她的DHCP服务器.并把她选定好的信息再次广播到各家各户.第四次广播是有幸被选择的DHCP服务器再次发出带有IP信息的广播包去确认下.绑定客户端网卡..经过这4次有问有答的交流，初次DHCP结束.绛旓細浣犲彧瑕佸紕娓呮DHCP鍘熺悊.浣犵殑闂涔熷氨娓呮浜...DHCP宸ヤ綔淇楄瘽璇粹滃洓娆℃彙鎵嬧濇病IP鐨勫鎴锋満鍙戦佺殑绗竴涓寘鏄悜鍏"涓栫晫"(缃戠粶锛夊箍鎾.浣滅敤鏄锛氬湪缃戠粶涓鎵綝HCP鏈嶅姟鍣.绗簩娆″箍鎾寘鏄墍鏈夋敹鍒板鎴风鍙戠殑骞挎挱鍖呯殑DHCP鏈嶅姟鍣ㄥ洖搴斿鎴风.骞舵彁渚涗竴涓甫鏈塈P淇℃伅鍙敤鐨勫箍鎾寘.绗笁娆℃槸瀹㈡埛绔夋嫨鐨勬満浼..濂逛細...
绛旓細锛1锛夊鎴风骞挎挱DHCP鍙戠幇锛圖HCP Discovery锛夛紙2锛夋湇鍔″櫒鍥炲簲DHCP鍝嶅簲锛圖HCP Offer锛夛紙3锛夊鎴风骞挎挱DHCP璇锋眰锛圖HCP Request锛夛紙4锛夋湇鍔″櫒鍥炲簲DHCP纭锛圖HCP ACK锛夊叾瀹炶繕鏈夊叾浠栫被鍨嬬殑鎶ユ枃锛屽鎴风鍙戠幇鍒嗛厤鐨処P鍦板潃宸茬粡琚崰鐢ㄦ椂锛屽彂閫丏HCP Decline锛岄氱煡鏈嶅姟鍣↖P鍦板潃宸茶鍗犵敤锛岃姹傞噸鏂板垎閰嶃傚鎴风鍙互涓诲姩閲...
绛旓細(2)IP绉熺敤鎻愪緵锛氱綉缁滀笂鎵鏈夌殑DHCP鏈嶅姟鍣ㄥ潎浼氭敹鍒版淇℃伅鍖锛屾瘡鍙癉HCP鏈嶅姟鍣ㄩ氳繃UDP绔彛68缁橠HCP瀹㈡埛 鏈哄洖搴斾竴涓狣HCPOFFER骞挎挱鍖咃紝鎻愪緵涓涓狪P鍦板潃銆(3)IP绉熺敤閫夋嫨锛氬鎴锋満浠庝笉姝竴鍙癉HCP鏈嶅姟鍣ㄦ帴鏀跺埌鎻愪緵涔嬪悗锛屼細閫夋嫨绗竴涓敹鍒扮殑DHCPOFFER鍖咃紝骞跺悜 缃戠粶涓箍鎾竴涓狣HCPREQUEST娑堟伅鍖咃紝琛ㄦ槑鑷繁宸茬粡鎺ュ彈...
绛旓細鎻愪緵IP鍦板潃锛涚涓夋锛 DHCPrequest 鍖咃紝瀹㈡埛绔悜鏈嶅姟鍣ㄨ姹侷P鍦板潃锛涚鍥涙锛 DHCPack 鍖咃紝纭鍖咃紝鏈嶅姟鍣ㄥ悜瀹㈡埛绔垎閰岻P鍦板潃銆侱HCP锛圖ynamic Host Configuration Protocol锛屽姩鎬佷富鏈洪厤缃崗璁級鏄竴涓眬鍩熺綉鐨勭綉缁滃崗璁紝浣跨敤UDP鍗忚宸ヤ綔銆備富瑕佹湁涓や釜鐢ㄩ旓細缁欏唴閮ㄧ綉缁滄垨缃戠粶鏈嶅姟渚涘簲鍟嗚嚜鍔ㄥ垎閰岻P鍦板潃锛岀粰鐢ㄦ埛...
绛旓細鎻愪緵IP 绉熺敤鍦板潃銆傚綋 DHCP 鏈嶅姟鍣ㄧ洃鍚埌瀹㈡埛绔彂鍑虹殑 DHCP discover 骞挎挱鍚,瀹冧細浠庨偅浜涜繕娌℃湁绉熷嚭鐨勫湴鍧鑼冨洿鍐,閫夋嫨鏈鍓嶉潰鐨勭┖缃 IP ,杩炲悓鍏跺畠 TCP/IP 璁惧畾,鍝嶅簲缁欏鎴风涓涓 DHCP OFFER 灏佸寘銆 鐢变簬瀹㈡埛绔湪寮濮嬬殑鏃跺欒繕娌℃湁 IP 鍦板潃,鎵浠ュ湪鍏 DHCP discover 灏佸寘鍐呬細甯︽湁鍏 MAC 鍦板潃淇℃伅,骞朵笖鏈変竴涓 XID...
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绛旓細255.255.255.255鏄彈闄愬箍鎾湴鍧锛屽叾涓昏鐢ㄤ簬涓绘満閰嶇疆杩囩▼涓璉P鏁版嵁鎶ョ殑鐩殑鍦板潃銆 DHCP绉熺害杩囩▼灏辨槸DHCP瀹㈡埛鏈哄姩鎬佽幏鍙朓P鍦板潃鐨勮繃绋嬨 DHCP绉熺害杩囩▼鍒嗕负4姝ワ細 鈶 瀹㈡埛鏈鸿姹侷P锛堝鎴锋満鍙 DHCPDISCOVER 骞挎挱鍖锛夛紱 鈶 鏈嶅姟鍣ㄥ搷搴旓紙鏈嶅姟鍣ㄥ彂 DHCPOFFER 骞挎挱鍖咃級锛 鈶 瀹㈡埛鏈洪夋嫨IP锛堝鎴锋満鍙 DHCP...
绛旓細DHCP鏄Dynamic Host Configuration Protocol鐨勭缉鍐欙紝瀹冩槸TCP锛廔P鍗忚绨囦腑鐨勪竴绉嶏紝涓昏鏄敤鏉ョ粰缃戠粶瀹㈡埛鏈哄垎閰嶅姩鎬佺殑IP鍦板潃銆傝繖浜涜鍒嗛厤鐨処P鍦板潃閮芥槸DHCP鏈嶅姟鍣ㄩ鍏堜繚鐣欑殑涓涓敱澶氫釜鍦板潃缁勬垚鐨勫湴鍧闆嗭紝骞朵笖瀹冧滑涓鑸槸涓娈佃繛缁殑鍦板潃銆俓x0d\x0a \x0d\x0a 鐞嗚ВDHCP鏈嶅姟\x0d\x0a \x0d\x0a ...
绛旓細鏍规嵁浼烘湇鍣ㄧ鐨勮瀹氾紝Dhcpoffer 灏佸寘浼氬寘鍚竴涓绾︽湡闄愮殑淇℃伅銆3. 鎺ュ彈 IP 绉熺害銆傚鏋滃鎴风鏀跺埌缃戣矾涓婂鍙 DHCP 浼烘湇鍣ㄧ殑鍥炲簲锛屽彧浼氭寫閫夊叾涓竴涓 Dhcpoffer 鑰屽凡(閫氬父鏄渶鍏堟姷杈剧殑閭ｄ釜)锛屽苟涓斾細鍚戠綉璺彂閫佷竴涓狣hcprequest骞挎挱灏佸寘锛屽憡璇夋墍鏈 DHCP 浼烘湇鍣ㄥ畠灏嗘寚瀹氭帴鍙楀摢涓鍙颁己鏈嶅櫒鎻愪緵鐨 IP 浣嶅潃銆
