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Steffen Winkler's questions

Martin Hope
Steffen Winkler
Asked: 2014-07-03 00:01:35 +0800 CST
  • 0

我原来的问题：FTP 客户端/服务器在切换到 PASV 模式时失败

基于此，我想知道是否/如何打开从使用 Dual-Stack Lite 的 ISP 网络内的计算机到只能通过 IPv4 访问的 FTP 服务器的 FTP 连接。

显然，被动 FTP 不起作用，但主动 FTP 会起作用吗（如果我在所有者的路由器上添加了端口转发）？

ftp
Martin Hope
Steffen Winkler
Asked: 2014-07-02 01:51:53 +0800 CST
  • 3

更新 ISP 表示他们最近将这台计算机所在的区域添加到他们的 IPv6 网络中。巧合的是，从他们将该区域添加到 IPv6 网络的那一天起，就无法建立 FTP 连接。

ISP 能够将此特定连接设置回 IPv4（在有限的时间内）并且...FTP 再次工作。

问题的原始描述

我在 FTP 客户端和 FTP 服务器之间存在 TCP 级别问题（我认为这是一个 proftp 服务器，但我不确定）。

在请求 PASV 模式进行数据传输时，客户端收到 ACK 但未收到227 entering passive mode消息。客户端等待 30 秒，然后再发送TYPE A request服务器尝试 ACK，但 SEQ 编号错误。

SEQ 编号包含Enter passive mode消息的大小。服务器还发送一个200 Switching to ASCII mode也有错误的 SEQ 编号。

从那里开始尝试 TCP 重传和 TCP DUP ACK 的 7 次尝试，而双方都使用“他们的”SEQ 编号。（服务器发送的未确认消息不应该重传吗？意思是，服务器不应该只是227 entering passive mode再次发送消息吗？或者至少修复SEQ号？）

我在这里有多个问题。一方面，哪一方的行为是错误的？一方必须修复它的 SEQ 编号，但是谁呢？特定消息（始终是Entering passive mode消息）怎么会总是丢失？

更奇怪的是，这只发生在一台计算机上。从数百中。而且它也只发生在一台 FTP 服务器上。（我无法控制）。服务器和相关计算机通过互联网连接。

日志是通过客户端的路由器获取的，因此不是 PC 问题。

好的，我设法过滤了协议。所以这里是：

No.     Time        Protocol Length Info
     39 5.988043    FTP      68     Request: PASV

Frame 39: 68 bytes on wire (544 bits), 68 bytes captured (544 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 68, Ack: 294, Len: 6
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     40 6.034184    TCP      62     ftp > 49736 [ACK] Seq=294 Ack=74 Win=32695 Len=0

Frame 40: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 294, Ack: 74, Len: 0

No.     Time        Protocol Length Info
     41 36.381924   FTP      70     Request: TYPE A

Frame 41: 70 bytes on wire (560 bits), 70 bytes captured (560 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 74, Ack: 294, Len: 8
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     42 36.417678   TCP      62     [TCP Previous segment lost] ftp > 49736 [ACK] Seq=345 Ack=82 Win=32687 Len=0

Frame 42: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 0

No.     Time        Protocol Length Info
     43 36.435735   FTP      92     Response: 200 Switching to ASCII mode.

Frame 43: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     44 36.436237   TCP      62     [TCP Dup ACK 41#1] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 44: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     45 37.274734   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 45: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     46 37.275388   TCP      62     [TCP Dup ACK 41#2] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 46: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     47 38.515559   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 47: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     48 38.516182   TCP      62     [TCP Dup ACK 41#3] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 48: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     49 40.376003   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 49: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     50 40.376567   TCP      62     [TCP Dup ACK 41#4] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 50: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     51 43.474007   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 51: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     52 43.474611   TCP      62     [TCP Dup ACK 41#5] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 52: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     53 49.053924   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 53: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     54 49.054515   TCP      62     [TCP Dup ACK 41#6] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 54: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     55 59.593195   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 55: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 345, Ack: 82, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     56 59.593832   TCP      62     [TCP Dup ACK 41#7] 49736 > ftp [ACK] Seq=82 Ack=294 Win=65047 Len=0

Frame 56: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     57 66.796925   FTP      70     Request: TYPE A

Frame 57: 70 bytes on wire (560 bits), 70 bytes captured (560 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 82, Ack: 294, Len: 8
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     58 66.833363   TCP      62     ftp > 49736 [ACK] Seq=375 Ack=90 Win=32679 Len=0

Frame 58: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 0

No.     Time        Protocol Length Info
     59 66.852889   FTP      92     Response: 200 Switching to ASCII mode.

Frame 59: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     60 66.853447   TCP      62     [TCP Dup ACK 57#1] 49736 > ftp [ACK] Seq=90 Ack=294 Win=65047 Len=0

Frame 60: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     61 67.653089   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 61: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     62 67.653593   TCP      62     [TCP Dup ACK 57#2] 49736 > ftp [ACK] Seq=90 Ack=294 Win=65047 Len=0

Frame 62: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     63 68.894847   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 63: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     64 68.895352   TCP      62     [TCP Dup ACK 57#3] 49736 > ftp [ACK] Seq=90 Ack=294 Win=65047 Len=0

Frame 64: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     65 70.755267   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 65: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     66 70.755790   TCP      62     [TCP Dup ACK 57#4] 49736 > ftp [ACK] Seq=90 Ack=294 Win=65047 Len=0

Frame 66: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     67 73.851892   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 67: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     68 73.852389   TCP      62     [TCP Dup ACK 57#5] 49736 > ftp [ACK] Seq=90 Ack=294 Win=65047 Len=0

Frame 68: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     69 79.432036   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 69: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 375, Ack: 90, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     70 79.432625   TCP      62     [TCP Dup ACK 57#6] 49736 > ftp [ACK] Seq=90 Ack=294 Win=65047 Len=0

Frame 70: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     71 87.075370   FTP      70     Request: TYPE A

Frame 71: 70 bytes on wire (560 bits), 70 bytes captured (560 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 90, Ack: 294, Len: 8
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     72 87.111901   TCP      62     ftp > 49736 [ACK] Seq=405 Ack=98 Win=32671 Len=0

Frame 72: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 0

No.     Time        Protocol Length Info
     73 87.131366   FTP      92     Response: 200 Switching to ASCII mode.

Frame 73: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     74 87.131840   TCP      62     [TCP Dup ACK 71#1] 49736 > ftp [ACK] Seq=98 Ack=294 Win=65047 Len=0

Frame 74: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     75 87.801062   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 75: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     76 87.801573   TCP      62     [TCP Dup ACK 71#2] 49736 > ftp [ACK] Seq=98 Ack=294 Win=65047 Len=0

Frame 76: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     77 89.041426   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 77: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     78 89.042081   TCP      62     [TCP Dup ACK 71#3] 49736 > ftp [ACK] Seq=98 Ack=294 Win=65047 Len=0

Frame 78: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     79 90.901416   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 79: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     80 90.901988   TCP      62     [TCP Dup ACK 71#4] 49736 > ftp [ACK] Seq=98 Ack=294 Win=65047 Len=0

Frame 80: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     81 94.000587   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 81: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     82 94.001269   TCP      62     [TCP Dup ACK 71#5] 49736 > ftp [ACK] Seq=98 Ack=294 Win=65047 Len=0

Frame 82: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     83 99.580475   FTP      92     [TCP Retransmission] Response: 200 Switching to ASCII mode.

Frame 83: 92 bytes on wire (736 bits), 92 bytes captured (736 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 405, Ack: 98, Len: 30
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     84 99.581110   TCP      62     [TCP Dup ACK 71#6] 49736 > ftp [ACK] Seq=98 Ack=294 Win=65047 Len=0

Frame 84: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 0

No.     Time        Protocol Length Info
     85 117.494304  FTP      70     Request: TYPE A

Frame 85: 70 bytes on wire (560 bits), 70 bytes captured (560 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: 49736 (49736), Dst Port: ftp (21), Seq: 98, Ack: 294, Len: 8
File Transfer Protocol (FTP)

No.     Time        Protocol Length Info
     86 117.531119  TCP      62     ftp > 49736 [RST] Seq=294 Win=0 Len=0

Frame 86: 62 bytes on wire (496 bits), 62 bytes captured (496 bits)
Ethernet II
PPP-over-Ethernet Session
Point-to-Point Protocol
Internet Protocol Version 4
Transmission Control Protocol, Src Port: ftp (21), Dst Port: 49736 (49736), Seq: 294, Len: 0

编辑

我检查了另一台受我控制的 FTP 服务器，现在事情变得很奇怪（阅读：它也不能与那个服务器一起工作）。根据我的服务器，它正在与一个以.0. 作为记录，我位于德国。我以前从未见过以 IPv4 地址结尾的地址.0。

如果我在客户端检查路由器，它会报告一个完全不同的公共 IPv4 地址（至少那个看起来有效），它还报告一个 IPv6 地址（在德国很少有。取决于 ISP。）

我的服务器的日志说它正在发送（并且也重新传输，因为它没有收到ACK）Entering passive mode消息。至少对我而言，这意味着 ISP 正在丢失/丢弃该软件包。

我应该联系 ISP 并提供该信息吗？

ftp
Martin Hope
Steffen Winkler
Asked: 2013-08-09 23:11:00 +0800 CST
  • 4

我在我们客户的一个备份硬盘上遇到了一个奇怪的问题：硬盘被格式化为 FAT32，昨晚我们的备份作业在子目录上抛出了一个错误，声称它无法复制它必须复制的文件。

我当然首先检查了磁盘大小，但是有足够的空间。给出的错误是 0x80070052，如果我把它放到搜索引擎中，我会得到如下结果：http ://www.quickonlinetips.com/archives/2007/09/how-to-fix-error-0x80070052-on-usb-闪存驱动器/

但是该分区的根目录中只有 8 个文件/目录。所以我继续并决定自己测试一些东西。创建单个文件（例如名为“test.txt”）确实有效。但是使用备份作业失败的文件名之一创建一个文件不起作用，相反我得到了与上面相同的错误。我测试了一下，发现我可以在该子目录中创建一个包含 10 个字符的文件，再多一个字符，它就会失败。

检测到这一点后，我在该子目录中创建了一个目录（名为“test”）并将一些文件从子目录移动到新目录中，完成后，我尝试创建一个包含 11 个字符的文件（这不起作用之前）并且它起作用了。

现在，显然从观察来看，对于 FAT32 的单个目录中的所有文件名可以使用多少个字符似乎存在某种硬限制，但我找不到有关该硬限制或其他文件系统（尤其是 NTFS ，我猜这将是这种情况下的替代方案）具有类似的限制。

如果有人可以向我提供有关观察到的行为的信息，那就太好了！

编辑

一位同事告诉我将确切的文件夹放在另一个 FAT32 驱动器上，因为他曾经遇到过特定制造商的 USB 控制器的问题。我尝试了两个来自不同制造商的 USB 记忆棒，都是 FAT32 格式，都显示出与上述完全相同的行为。

为了让您了解所涉及的文件数量：大约有 10200 个文件，每个文件的文件名长度在 80 到 110 个字符之间，不包括文件路径（这似乎无关紧要），所以大约有涉及一百万个字符。

limits
Martin Hope
Steffen Winkler
Asked: 2013-07-21 10:18:20 +0800 CST
  • 1

我已经从默认存储库在我的 Ubuntu 13.04 上安装了 qemu 和 AQEMU。我使用向导创建了一个虚拟机，并将硬盘设置为 10 GiB。

我在设备管理器中添加了一个 Debian 7.1 .iso 文件并启动了机器。正如预期的那样，iso 文件被识别，我能够开始安装过程。

整个安装过程没有任何错误或警告。分区，一切都很棒。

即使我重新启动虚拟机，安装完成后，我也能够启动到新系统。在玩弄了一番之后，我将其关闭以删除 iso 映像，当我尝试重新启动时，“BIOS”说没有分区可以启动。我环顾四周，发现应该保存虚拟磁盘的 .img 文件只有 197.1 kB。

以为我犯了一些错误，我再次完成了整个过程……一次又一次……一次又一次。我尝试创建快照（这有效，至少我没有收到任何错误）但是当我在关闭 VM 后尝试从这些快照开始时，我只是得到一个黑屏，没有别的。此外，img 文件的大小也从未改变。

我尝试单击“保存”，这只是提示我无法在快照模式下保存（wtf？）。

我现在有点不知所措。我也很沮丧。安装过程在哪里？为什么没有错误信息？我究竟做错了什么？我必须使用一些隐藏的命令吗？我什至无法通过远程连接到我的问题的搜索引擎找到任何东西。而且我在标准输出上也没有任何错误。

.img 文件在我的主目录中，所以我有读/写权限。

kvm-virtualization
Martin Hope
Steffen Winkler
Asked: 2012-08-31 04:24:31 +0800 CST
  • 3

我使用的是 Apache 2.2 而不是 2.4，这解释了标题中的错误。在 Brain99 发表他的评论后，我发现我有 2.2，按照他的建议调整我的配置（仍然没有用），试了一下，睡了一晚，第二天我发现，我忘记了包含启用 mod 的目录的语句！

现在我只需要服务器让我从一个特定的文件夹下载文件（在我的例子中我选择 /opt/myFolder 来完成该任务）

发行版是 Debian 6.0

编辑开始

Apache 版本是 2.4，根据他们的官方文档，Order/Allow 子句已被弃用，不应再使用

我是个白痴：Apache 版本是 2.2。

edit_end 我在 apache2.conf 中的目录指令如下所示：

<IfModule dir_module>
                DirectoryIndex index.html index.htm index.php
</IfModule>
ServerRoot "/etc/apache2"
DocumentRoot "/opt/myFolder"
<Directory />
        Options FollowSymLinks
        AuthType None
        AllowOverride None
        Require all denie
</Directory>
<Directory "/opt/myFolder/*">
        Options FollowSymLinks MultiViews
        AllowOverride None
        AuthType None
        Require all allow
</Directory>

当我尝试访问该文件夹 ( http://myserver.de/aTestFile.zip ) 中的文件时，出现内部服务器错误。Apache 还将以下错误写入其日志：

configuration error:  couldn't check user.  Check your authn provider!: /aTestFile.zip

如果我不需要任何身份验证，为什么还需要身份验证提供程序？我也希望有人可以向我解释我需要什么样的 AuthenticationProvider。每次我搜索这些东西时，都会有人问我如何使用密码保护文件/目录或限制对某些 IP 地址的访问，这对我没有多大帮助。

好的，因为我有 Apache 2.2 版，这是我在使用 Order/Deny/Allow 命令而不是 AuthType/Require 命令时得到的错误：

Invalid command 'Order', perhaps misspelled or defined by a module not included in the server configuration.
apache-2.2