ftp连接问题，vsftp服务器，主动模式

我有一个运行vsftpd来处理ftp连接的服务器。 我的一个用户有一个安装了Total Commander和WinSCP的笔记本。 两个FTP客户端连接build立到服务器后立即失败，并尝试下载目录列表，并显示以下错误消息：

Timeout detected. Could not retrieve directory listing PORT command successful. Consider using PASV. Error listing directory '/'. 

奇怪的是：笔记本的工作完全可以与其他FTP服务器。 我的FTP服务器也适用于其他客户端。 实际上，这个用户也有一台与笔记本在同一个局域网上运行的电脑，而且这台电脑和ftp服务器的配合良好。

我们使用PORT ftp连接模式。 被动模式运行良好，但在这一点上不是一种select。

我会发布更多的技术细节，但我甚至不知道这个问题是与什么有关的。 无论如何，下面是服务器端tcpdump失败的连接尝试。 在最后一行日志之后，客户端和服务器之间没有进一步的通信。

• 很多连接到6881端口 – 一些新的攻击还是什么？
• 客户端的端口22被阻塞 – 连接到SVN
• 在CentOS 5.5 / Webmin中基于端口的虚拟主机
• 无法安装新的SSL证书（Apache2虚拟主机）
• 仅当计算机连接到另一个vnc服务器时才能连接到VNC

非常感谢您的任何提示！

 23:39:24.514852 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: S 1314489715:1314489715(0) win 65535 <mss 1460,nop,wscale 3,nop,nop,sackOK> 23:39:24.514896 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: S 2633658883:2633658883(0) ack 1314489716 win 5840 <mss 1460,nop,nop,sackOK,nop,wscale 2> 23:39:24.520842 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: . ack 1 win 62500 23:39:24.523803 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 1:21(20) ack 1 win 1460 23:39:24.546858 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 1:15(14) ack 21 win 62497 23:39:24.546902 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: . ack 15 win 1460 23:39:24.547247 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 21:55(34) ack 15 win 1460 23:39:24.762806 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: . ack 55 win 62493 23:39:30.415011 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 15:28(13) ack 55 win 62493 23:39:30.454116 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: . ack 28 win 1460 23:39:31.036283 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 55:78(23) ack 28 win 1460 23:39:31.053018 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 28:34(6) ack 78 win 62490 23:39:31.053042 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: . ack 34 win 1460 23:39:31.053268 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 78:97(19) ack 34 win 1460 23:39:31.068969 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 34:40(6) ack 97 win 62488 23:39:31.069148 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 97:112(15) ack 40 win 1460 23:39:31.069179 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 112:119(7) ack 40 win 1460 23:39:31.076981 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: . ack 119 win 62485 23:39:31.077010 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 119:177(58) ack 40 win 1460 23:39:31.114979 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 40:45(5) ack 177 win 62478 23:39:31.115164 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 177:186(9) ack 45 win 1460 23:39:31.180966 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 45:53(8) ack 186 win 62476 23:39:31.181066 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 186:216(30) ack 53 win 1460 23:39:31.213065 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 53:80(27) ack 216 win 62473 23:39:31.213180 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 216:267(51) ack 80 win 1460 23:39:31.251086 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: P 80:86(6) ack 267 win 62466 23:39:31.251498 IP 195.70.xx.xx.20 > 62.201.xx.xx.5001: S 2640780713:2640780713(0) win 5840 <mss 1460,sackOK,timestamp 2054371220 0,nop,wscale 2> 23:39:31.290979 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: . ack 86 win 1460 23:39:34.251489 IP 195.70.xx.xx.20 > 62.201.xx.xx.5001: S 2640780713:2640780713(0) win 5840 <mss 1460,sackOK,timestamp 2054374220 0,nop,wscale 2> 23:39:40.249625 IP 195.70.xx.xx.20 > 62.201.xx.xx.5001: S 2640780713:2640780713(0) win 5840 <mss 1460,sackOK,timestamp 2054380220 0,nop,wscale 2> 23:39:43.695108 IP 195.70.xx.xx.21 > 62.201.xx.xx.1057: P 2280716551:2280716588(37) ack 3838413728 win 5840 23:39:52.248791 IP 195.70.xx.xx.20 > 62.201.xx.xx.5001: S 2640780713:2640780713(0) win 5840 <mss 1460,sackOK,timestamp 2054392220 0,nop,wscale 2> 23:40:16.245159 IP 195.70.xx.xx.20 > 62.201.xx.xx.5001: S 2640780713:2640780713(0) win 5840 <mss 1460,sackOK,timestamp 2054416221 0,nop,wscale 2> 23:40:29.853685 IP 195.70.xx.xx.21 > 62.201.xx.xx.1057: FP 37:51(14) ack 1 win 5840 23:40:31.241951 IP 195.70.xx.xx.21 > 62.201.xx.xx.2241: P 267:304(37) ack 86 win 1460 23:40:31.381708 IP 62.201.xx.xx.2241 > 195.70.xx.xx.21: . ack 304 win 62462