php用 fsockopen smtp 发邮件遇到个问题

[闲人三分]

 $fp  =  fsockopen ( $smtp ,  $port ,  $errno ,  $errstr ,  30 );
        if (! $fp ) {
            echo  " $errstr  ( $errno )<br />\n" ;
        } else {
             
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            //print_r($re_arr);
            if ($re_arr[0]!=220) {
                $state['state']=0;
                $state['info'] ="连接到邮件服务器失败";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

           
            //send HELO sb
            fwrite ( $fp ,  "HELO sb\r\n" );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=250) {
                $state['state']=0;
                $state['info'] ="邮件服务器无响应";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

           
            fwrite ( $fp ,  "auth login\r\n" );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=334) {
                $state['state']=0;
                $state['info'] ="邮件服务器拒绝登录";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }
  

            //发送用户名
            fwrite ( $fp ,  base64_encode($email_user)."\r\n" );
            $re =  fgets ( $fp ,  256 );
            // 这里遇到个问题 这个$re 有时返回是空的 没有任何内容
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=334) {
                $state['state']=0;
                $state['info'] ="用户名验证失败";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

            //发送密码
            fwrite ( $fp ,  base64_encode($password)."\r\n" );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=235) {
                $state['state']=0;
                if ($re_arr[0]=="454") {
                    $state['info'] ="请开启smtp";
                }else{
                    $state['info'] ="用户名或密码验证失败";
                }

                fclose ( $fp );
                print_r($re_arr);
                print_r($state);
                exit();
                return $state;

            }

            //mail from:<[e-mail]>
            fwrite ( $fp ,  "mail from:<".$email.">\r\n" );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=250) {
                $state['state']=0;
                $state['info'] ="mail from 消息验证失败";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

            //rcpt to:<[e-mail]>
            fwrite ( $fp ,  "rcpt to:<".$to.">\r\n" );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=250) {
                $state['state']=0;
                $state['info'] ="rcpt to 消息验证失败";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

            //data 命令
            fwrite ( $fp ,  "data\r\n" );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=354) {
                $state['state']=0;
                $state['info'] ="邮件服务器拒绝";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

            // 发送数据
            fwrite ( $fp ,  $mail_body );
            $re =  fgets ( $fp ,  256 );
            $re_arr = explode(" ",$re);
            if ($re_arr[0]!=250) {
                $state['state']=0;
                $state['info'] ="邮件发送失败";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }else{
                $state['state']=1;
                $state['info'] ="邮件发送成功";
                fclose ( $fp );
                print_r($state);
                exit();
                return $state;

            }

在 发送用户名 那里遇到个问题。经过反复测试后发现 fgets();有时返回值是空的，没有这个 “334 xxxxx” 这种内容。下面发送密码也是这样的 。在家里的电脑上没出现这种问题，在公司的电脑和在服务器上就出现了。代码写成这样主要是为了方便看。求高手帮忙解答。