我的解决办法，初步测试没有问题了，不知道会不会有其他问题。
修改wForum/logon.php
diff如下：
54c54,86
<       $ret=bbs_wwwlogin($kick);
---
> /* get from www2-funcs.php by ycflash */
>         global $proxyIPs;
>         global $fullfromhost;
>         global $fromhost;
>
>         @$fullfromhost=$_SERVER["HTTP_X_FORWARDED_FOR"];
>         if ($fullfromhost=="") {
>                 @$fullfromhost=$_SERVER["REMOTE_ADDR"];
>                 $fromhost=$fullfromhost;
>         }
>         else {
>                 $ips = explode(",", $fullfromhost);
>                 $c = count($ips);
>                 if ($c > 1) {
>                         $fromhost = trim($ips[$c - 1]);
>                         if (isset($proxyIPs) && in_array($fromhost, $proxyIPs)) {
>                                 $fromhost = $ips[$c - 2];
>                         }
>                 } else $fromhost = $fullfromhost;
>         }
>         if ($fromhost=="")  {
>                 $fromhost="127.0.0.1";
>                 $fullfromhost="127.0.0.1";
>         }
>         if (defined("IPV6_LEGACY_IPV4_DISPLAY")) {
>                 if ((strchr($fromhost, '.'))&&($p=strrchr($fromhost, ':')))
>                         $fromhost=substr($p, 1);
>         }
>         //sometimes,fromhost has strang space
>         bbs_setfromhost(trim($fromhost),trim($fullfromhost));
>       $ret=bbs_wwwlogin(($kick_multi!="") ? 1 : 0, $fromhost, $fullfromhost);
> /* end by ycflash */
> //    $ret=bbs_wwwlogin($kick);


这段代码其实从经典界面抄袭过来的，嘿嘿



【 在 ycflash (unknown) 的大作中提到: 】
: 目前我们论坛升级支持v6，telnet和ssh及经典web上没有问题了
: 不过用v6方式登陆论坛的wforum，得到的ip是v4的地址而且是错误的地址。
: 在wforum的文件里找了半天也没有找出哪里可能有问题。
: ...................
--
修改:ycflash FROM 210.76.114.*
FROM 210.76.114.*