我有一外網(wǎng)IP:218.17.xxx.xxx，現(xiàn)在想用這個(gè)IP通過(guò)linux映射到內(nèi)部的一臺(tái)WEB服務(wù)器上IP為:192.168.188.5,就是不管在外面還是內(nèi)部都是用218.17.xxx.xxx來(lái)訪問(wèn)WEB(這WEB在內(nèi)部的192.168.188.5上),怎么做?
?江湖無(wú)賴(lài) 回復(fù)于：2003-09-18 11:35:52Q：一局域網(wǎng)192.168.1.0/24，有web和ftp服務(wù)器192.168.1.10、192.168.1.11,網(wǎng)關(guān)linux，內(nèi)網(wǎng)eth0，IP為192.168.1.1，外網(wǎng)eth1，IP為a.b.c.d，怎樣作NAT能使內(nèi)外網(wǎng)都能訪問(wèn)公司的服務(wù)器？
A：#?web
#?用DNAT作端口映射
iptables?-t?nat?-A?PREROUTING?-d?a.b.c.d?-p?tcp?--dport?80?-j?DNAT?--to?192.168.1.10
#?用SNAT作源地址轉(zhuǎn)換（關(guān)鍵），以使回應(yīng)包能正確返回
iptables?-t?nat?-A?POSTROUTING?-d?192.168.1.10?-p?tcp?--dport?80?-j?SNAT?--to?192.168.1.1
#?一些人經(jīng)常忘了打開(kāi)FORWARD鏈的相關(guān)端口，特此增加
iptables?-A?FORWARD?-o?eth0?-d?192.168.1.10?-p?tcp?--dport?80?-j?ACCEPT
iptables?-A?FORWARD?-i?eth0?-s?192.168.1.10?-p?tcp?--sport?80?-m?--state?ESTABLISHED?-j?ACCEPT
#?ftp
modprobe?ip_nat_ftp?###加載ip_nat_ftp模塊（若沒(méi)有編譯進(jìn)內(nèi)核），以使ftp能被正確NAT
modprobe?ip_conntrack_ftp?###加載ip_conntrack_ftp模塊
#?用DNAT作端口映射
iptables?-t?nat?-A?PREROUTING?-d?a.b.c.d?-p?tcp?--dport?21?-j?DNAT?--to?192.168.1.11
iptables?-A?FORWARD?-o?eth0?-d?192.168.1.11?-p?tcp?--dport?21?-j?ACCEPT
iptables?-A?FORWARD?-i?eth0?-s?192.168.1.11?-p?tcp?--sport?21?-m?--state?ESTABLISHED?-j?ACCEPT
iptables?-A?FORWARD?-i?eth0?-s?192.168.1.11?-p?tcp?--sport?20?-m?--state?ESTABLISHED,RELATED?-j?ACCEPT
iptables?-A?FORWARD?-o?eth0?-d?192.168.1.11?-p?tcp?--dport?20?-m?--state?ESTABLISHED?-j?ACCEPT
iptables?-A?FORWARD?-o?eth0?-d?192.168.1.11?-p?tcp?--dport?1024:?-m?--state?ESTABLISHED,RELATED?-j?ACCEPT
iptables?-A?FORWARD?-i?eth0?-s?192.168.1.11?-p?tcp?--sport?1024:?-m?--state?ESTABLISHED?-j?ACCEPT
#?用SNAT作源地址轉(zhuǎn)換（關(guān)鍵），以使回應(yīng)包能正確返回
iptables?-t?nat?-A?POSTROUTING?-d?192.168.1.11?-p?tcp?--dport?21?-i?eth0?-j?SNAT?--to?192.168.1.1?
Q：網(wǎng)絡(luò)環(huán)境如上一問(wèn)題，還在網(wǎng)關(guān)上用squid進(jìn)行透明代理，也作了SNAT了，為什么內(nèi)網(wǎng)還是不能訪問(wèn)公司的web服務(wù)器?iptables如下：
iptables?-t?nat?-A?PREROUTING?-s?192.168.1.0/24?-p?tcp?--dport?80?-i?eth0?-j?REDIRECT?--to?3128
iptables?-t?nat?-A?PREROUTING?-d?a.b.c.d?-p?tcp?--dport?80?-j?DNAT?--to?192.168.1.10
iptables?-t?nat?-A?POSTROUTING?-d?192.168.1.10?-p?tcp?--dport?80?-j?SNAT?--to?192.168.1.1
A：?jiǎn)栴}主要在PREROUTING鏈中REDIRECT和DNAT的順序，由于先進(jìn)行了REDIRECT（重定向），則到第二句DNAT時(shí)，端口已變?yōu)?128，不匹配第二句的目的端口80，DNAT也就不會(huì)執(zhí)行，不能到達(dá)正確的目的地。解決的辦法有兩個(gè)：
1、把REDIRECT語(yǔ)句放到DNAT語(yǔ)句的后面，如下：
iptables?-t?nat?-A?PREROUTING?-d?a.b.c.d?-p?tcp?--dport?80?-j?DNAT?--to?192.168.1.10
iptables?-t?nat?-A?PREROUTING?-s?192.168.1.0/24?-p?tcp?--dport?80?-i?eth0?-j?REDIRECT?--to?3128
2、在REDIRECT語(yǔ)句中增加匹配目的地址"-d?!?a.b.c.d"，如下：
iptables?-t?nat?-A?PREROUTING?-s?192.168.1.0/24?-d?!?a.b.c.d?-p?tcp?--dport?80?-i?eth0?-j?REDIRECT?--to?3128
iptables?-t?nat?-A?PREROUTING?-d?218.17.xxx.xxx??-p?tcp?--dprot?80?-j?DNAT?--to??192.168.188.5:80
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