PhpHTTP_X_FORWARDED_FOR, HTTP_VIA, REMOTE_ADDR differences

I. no proxy server is used: REMOTE_ADDR your IPHTTP_VIA has no value or does not show HTTP_X_FORWARDED_FOR has no value or does not show 2. Transparent use

I. no proxy server is used:

REMOTE_ADDR = your IP address

HTTP_VIA = no value or no Display

HTTP_X_FORWARDED_FOR = no value or no Display

II. Transparent Proxy Server: Transparent Proxies

REMOTE_ADDR = IP address of the last proxy server

HTTP_VIA = proxy server IP address

HTTP_X_FORWARDED_FOR = your real IP address. when multiple proxy servers are used, this value is similar to the following: 203.98.1820.3, 203.98.1820.3, 203.129.72.215.

This type of proxy server still forwards your information to your access object, which cannot hide your real identity.

III. general anonymous proxy servers:

REMOTE_ADDR = IP address of the last proxy server

HTTP_VIA = proxy server IP address

HTTP_X_FORWARDED_FOR = proxy server IP address. when multiple proxy servers are used, this value is similar to the following: 203.98.1820.3, 203.98.1820.3, 203.129.72.215.

Your real IP address is hidden, but you are disclosed to the access object that you use the proxy server to access them.

IV. use of fraudulent proxy servers:

REMOTE_ADDR = proxy server IP address

HTTP_VIA = proxy server IP address

HTTP_X_FORWARDED_FOR = random IP address. when multiple proxy servers are used, the value is as follows: 203.98.182.163, 203.98.182.163, 203.129.72.215.

It tells the access object that you used the proxy server, but fabricated a false random IP address instead of your real IP address to cheat it.

5. use of highly anonymous proxy servers:

REMOTE_ADDR = proxy server IP address

HTTP_VIA = no value or no Display

HTTP_X_FORWARDED_FOR = no value or no value is displayed. when multiple proxy servers are used, the value is similar to the following: 203.98.182.163, 203.98.182.163, 203.129.72.215.

The proxy server information replaces all your information, just as you directly access the object using the proxy server.

Example 1: obtain the real IP address of a user,The code is as follows:

1. Function getIp (){
2. If ($ _ SERVER ['http _ CLIENT_IP ']) {
3. $ Ip = $ _ SERVER ['http _ CLIENT_IP ']; // PHP obtains the IP address
4. } Elseif ($ _ SERVER ['http _ X_FORWARDED_FOR ']) {
5. $ Ip = $ _ SERVER ['http _ X_FORWARDED_FOR '];
6. } Else {
7. $ Ip = $ _ SERVER ['remote _ ADDR ']; // PHP obtains the IP address
8. }
9. }

Example 2: The code is as follows:

2. /*
3. Mktime: 2012/9/9
4. */
5. // Obtain the user's real IP address
6. Function get_client_ip (){
7. If (getenv ("HTTP_CLIENT_IP") & strcasecmp (getenv ("HTTP_CLIENT_IP"), "unknown "))
8. $ Ip = getenv ("HTTP_CLIENT_IP ");
9. Else
10. If (getenv ("HTTP_X_FORWARDED_FOR") & strcasecmp (getenv ("HTTP_X_FORWARDED_FOR"), "unknown "))
11. $ Ip = getenv ("HTTP_X_FORWARDED_FOR ");
12. Else
13. If (getenv ("REMOTE_ADDR") & strcasecmp (getenv ("REMOTE_ADDR"), "unknown "))
14. $ Ip = getenv ("REMOTE_ADDR ");
15. Else
16. If (isset ($ _ SERVER ['remote _ ADDR ']) & $ _ SERVER ['remote _ ADDR '] & strcasecmp ($ _ SERVER ['remote _ ADDR'], "unknown "))
17. $ Ip = $ _ SERVER ['remote _ ADDR '];
18. Else
19. $ Ip = "unknown ";
20. Return ($ ip );
21. }
22. Echo $ ip = get_client_ip (); // This is your ip address.
23. ?>