Jou*_*eek 7 security router wireless-networking
我最近拿起了一组tenda MW6网状单元-我在“桥接”模式下运行它,因为这是关闭其dhcp服务器的唯一选项。连接到 DIY linux 路由器(ubuntu,带 firewalld。完整设置在这里)的主要网格单元- 这使我可以运行一些更有趣的工具来监控我的流量。linux 路由器提供 DHCP 和 DNS,并有 3 个桥接到单个接口的端口,主要网状单元位于这些端口之一。我显然可以运行 tcpdump 并获取通过网格单元的流量。
我正在桥接模式下运行网状单元,如果这很重要,并且到辅助设备的回程是通过无线进行的。Tendas 是通过电话应用程序管理的,但它是本地的,没有设置云帐户。
Router - Runs ubuntu + firewalld
192.168.1.1
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v
Primary Mesh Node (Tenda MW6) 192.168.1.99
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Secondary | Secondary
192.168.1.91 <-----+-----> 192.168.1.87
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我注意到使用 iftop 设备与 45.113.192.102 通信 - 这个 IP 似乎属于一个名为 baidu 的中文搜索引擎,tcpdump 表明所有 3 个节点都通过 http 连接到 IP。腾达声称其办法检查互联网connectivi TY
01:43:00.987943 IP 192.168.1.99.34783 > 45.113.192.102.http: Flags [F.], seq 1, ack 1, win 913, length 0
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是我的主路由器上 tcpdump 的输出示例。
运行 tcpdump ( sudo tcpdump -i br0 host 45.113.192.102 -s 0 -w dumpfile
) 并通过 wireshark 运行转储显示
No. Time Source Destination Protocol Length Info
1 0.000000 192.168.1.99 45.113.192.102 TCP 66 36256 ? 80 [SYN] Seq=0 Win=14600 Len=0 MSS=1460 SACK_PERM=1 WS=16
2 0.071250 45.113.192.102 192.168.1.99 TCP 66 80 ? 36256 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1452 SACK_PERM=1 WS=32
3 0.075499 192.168.1.99 45.113.192.102 TCP 60 36256 ? 80 [ACK] Seq=1 Ack=1 Win=14608 Len=0
4 0.075573 192.168.1.99 45.113.192.102 TCP 60 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
5 0.352218 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
6 0.632204 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
7 1.192806 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
8 2.312628 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
9 2.893126 192.168.1.99 45.113.192.102 TCP 60 36255 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=913 Len=0
10 4.552308 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
11 5.732298 192.168.1.99 45.113.192.102 TCP 60 36254 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=913 Len=0
12 9.042919 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
13 11.373253 192.168.1.99 45.113.192.102 TCP 60 36252 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=913 Len=0
14 15.155209 192.168.1.99 45.113.192.102 TCP 66 36257 ? 80 [SYN] Seq=0 Win=14600 Len=0 MSS=1460 SACK_PERM=1 WS=16
15 15.227698 45.113.192.102 192.168.1.99 TCP 66 80 ? 36257 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1452 SACK_PERM=1 WS=32
16 15.231005 192.168.1.99 45.113.192.102 TCP 60 36257 ? 80 [ACK] Seq=1 Ack=1 Win=14608 Len=0
17 15.231078 192.168.1.99 45.113.192.102 TCP 60 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
18 15.492991 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
19 15.763425 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
20 16.303042 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
21 17.382364 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
22 18.013092 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
23 19.542368 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
24 23.893447 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36257 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
25 26.493192 192.168.1.99 45.113.192.102 TCP 60 36253 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=913 Len=0
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数据包看起来像
No. Time Source Destination Protocol Length Info
1 0.000000 192.168.1.99 45.113.192.102 TCP 66 36256 ? 80 [SYN] Seq=0 Win=14600 Len=0 MSS=1460 SACK_PERM=1 WS=16
Frame 1: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
Ethernet II, Src: TendaTec_56:35:08 (04:95:e6:56:35:08), Dst: Gifa_01:07:60 (40:62:31:01:07:60)
Internet Protocol Version 4, Src: 192.168.1.99, Dst: 45.113.192.102
Transmission Control Protocol, Src Port: 36256, Dst Port: 80, Seq: 0, Len: 0
Source Port: 36256
Destination Port: 80
[Stream index: 0]
[TCP Segment Len: 0]
Sequence number: 0 (relative sequence number)
Acknowledgment number: 0
1000 .... = Header Length: 32 bytes (8)
Flags: 0x002 (SYN)
Window size value: 14600
[Calculated window size: 14600]
Checksum: 0x6b93 [unverified]
[Checksum Status: Unverified]
Urgent pointer: 0
Options: (12 bytes), Maximum segment size, No-Operation (NOP), No-Operation (NOP), SACK permitted, No-Operation (NOP), Window scale
No. Time Source Destination Protocol Length Info
2 0.071250 45.113.192.102 192.168.1.99 TCP 66 80 ? 36256 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1452 SACK_PERM=1 WS=32
Frame 2: 66 bytes on wire (528 bits), 66 bytes captured (528 bits)
Ethernet II, Src: Gifa_01:07:60 (40:62:31:01:07:60), Dst: TendaTec_56:35:08 (04:95:e6:56:35:08)
Internet Protocol Version 4, Src: 45.113.192.102, Dst: 192.168.1.99
Transmission Control Protocol, Src Port: 80, Dst Port: 36256, Seq: 0, Ack: 1, Len: 0
Source Port: 80
Destination Port: 36256
[Stream index: 0]
[TCP Segment Len: 0]
Sequence number: 0 (relative sequence number)
Acknowledgment number: 1 (relative ack number)
1000 .... = Header Length: 32 bytes (8)
Flags: 0x012 (SYN, ACK)
Window size value: 8192
[Calculated window size: 8192]
Checksum: 0xfa3d [unverified]
[Checksum Status: Unverified]
Urgent pointer: 0
Options: (12 bytes), Maximum segment size, No-Operation (NOP), No-Operation (NOP), SACK permitted, No-Operation (NOP), Window scale
[SEQ/ACK analysis]
No. Time Source Destination Protocol Length Info
3 0.075499 192.168.1.99 45.113.192.102 TCP 60 36256 ? 80 [ACK] Seq=1 Ack=1 Win=14608 Len=0
Frame 3: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
Ethernet II, Src: TendaTec_56:35:08 (04:95:e6:56:35:08), Dst: Gifa_01:07:60 (40:62:31:01:07:60)
Internet Protocol Version 4, Src: 192.168.1.99, Dst: 45.113.192.102
Transmission Control Protocol, Src Port: 36256, Dst Port: 80, Seq: 1, Ack: 1, Len: 0
Source Port: 36256
Destination Port: 80
[Stream index: 0]
[TCP Segment Len: 0]
Sequence number: 1 (relative sequence number)
Acknowledgment number: 1 (relative ack number)
0101 .... = Header Length: 20 bytes (5)
Flags: 0x010 (ACK)
Window size value: 913
[Calculated window size: 14608]
[Window size scaling factor: 16]
Checksum: 0x5775 [unverified]
[Checksum Status: Unverified]
Urgent pointer: 0
[SEQ/ACK analysis]
No. Time Source Destination Protocol Length Info
4 0.075573 192.168.1.99 45.113.192.102 TCP 60 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
Frame 4: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
Ethernet II, Src: TendaTec_56:35:08 (04:95:e6:56:35:08), Dst: Gifa_01:07:60 (40:62:31:01:07:60)
Internet Protocol Version 4, Src: 192.168.1.99, Dst: 45.113.192.102
Transmission Control Protocol, Src Port: 36256, Dst Port: 80, Seq: 1, Ack: 1, Len: 0
Source Port: 36256
Destination Port: 80
[Stream index: 0]
[TCP Segment Len: 0]
Sequence number: 1 (relative sequence number)
Acknowledgment number: 1 (relative ack number)
0101 .... = Header Length: 20 bytes (5)
Flags: 0x011 (FIN, ACK)
Window size value: 913
[Calculated window size: 14608]
[Window size scaling factor: 16]
Checksum: 0x5774 [unverified]
[Checksum Status: Unverified]
Urgent pointer: 0
No. Time Source Destination Protocol Length Info
5 0.352218 192.168.1.99 45.113.192.102 TCP 60 [TCP Retransmission] 36256 ? 80 [FIN, ACK] Seq=1 Ack=1 Win=14608 Len=0
Frame 5: 60 bytes on wire (480 bits), 60 bytes captured (480 bits)
Ethernet II, Src: TendaTec_56:35:08 (04:95:e6:56:35:08), Dst: Gifa_01:07:60 (40:62:31:01:07:60)
Internet Protocol Version 4, Src: 192.168.1.99, Dst: 45.113.192.102
Transmission Control Protocol, Src Port: 36256, Dst Port: 80, Seq: 1, Ack: 1, Len: 0
Source Port: 36256
Destination Port: 80
[Stream index: 0]
[TCP Segment Len: 0]
Sequence number: 1 (relative sequence number)
Acknowledgment number: 1 (relative ack number)
0101 .... = Header Length: 20 bytes (5)
Flags: 0x011 (FIN, ACK)
Window size value: 913
[Calculated window size: 14608]
[Window size scaling factor: 16]
Checksum: 0x5774 [unverified]
[Checksum Status: Unverified]
Urgent pointer: 0
[SEQ/ACK analysis]
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没有明显的有效载荷
有什么办法可以检查交通情况,以及发生了什么?
看起来它只是检查它是否在线并且可以在端口 80 上访问 45.113.192.102。
大概这只是 AP 进行“互联网可访问”测试,例如您经常在 Windows 中看到(它将连接到 Microsoft 地址)。
在每个数据包中都可以看到 - 没有 LEN=0 所示的数据。
3 0.075499 192.168.1.99 45.113.192.102 TCP 60 36256 ? 80 [ACK] Seq=1 Ack=1 Win=14608 Len=0
如果有数据,它通常会存储在数据包的这一部分中。他们可以通过在他们生成的数据包的序列号中隐藏加密信息来做一些事情,但这对于这种设备来说会非常慢而且不太可能。
如果有固件更新或类似更新,它们可能会以一些数据有效负载进行响应,在这种情况下,您会看到这些数据包中的数据返回:
15 15.227698 45.113.192.102 192.168.1.99 TCP 66 80 ? 36257 [SYN, ACK] Seq=0 Ack=1 Win=8192 Len=0 MSS=1452 SACK_PERM=1 WS=32
但目前它们似乎是空的,并且是beign。
您可以根据需要阻止对 45.113.192.102 或更大子网的访问,但这可能会导致 AP 认为它处于脱机状态,或者无法以某种方式正确连接,从而导致更多的麻烦。
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