RN/Blatt01/blatt01.md
2024-10-30 10:12:21 +01:00

7.8 KiB
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router table

device eth ip
PC1 eth1 10.5.0.2/24
PC2 eth1 10.5.1.2/24
router1 eth1 10.5.0.1/24
router2 eth1 10.5.1.1/24

router -> router

sender #   sender eth #    receiver #      receiver eth #          losses #                                            
1       2       2       2       20                                                                                           
1       3       3       2       20                                                                                           
1       4       4       1       0                                                                                            
2       2       1       2       20                                                                                           
2       3       3       3       0                                                                                            
2       4       4       2       0                                                                                            
3       2       1       3       0                                                                                            
3       3       2       3       0                                                                                            
3       4       4       3       0                                                                                            
4       1       1       4       0                                                                                            
4       2       2       4       0                                                                                            
4       3       3       4       0 

router -> pc


sender #   sender eth #    receiver #   receiver eth #  losses #                                                             │
1          1               1            1               0                                                                    │
2          1               1            1               0                                                                    │
2          1               2            1               0                                                                    │
2          1               3            1               0                                                                    │
3          1               3            1               0   

pc->pc


sender #   sender eth #    receiver #   receiver eth #  losses #                                                             
2          1               1            1               0                                                                    
2          1               3            1               0     

pc->router

sender #   sender eth #    receiver #   receiver eth #  losses #
2          1               2            1               0
3          1               3            1               0

Tcpdump output

with -e

listening on eth1, link-type EN10MB (Ethernet), snapshot length 262144 bytes                             
10:51:44.767031 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 18, length 64                         
10:51:44.767055 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 18, length 64                           
10:51:45.767125 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 19, length 64                         
10:51:45.767160 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 19, length 64                           10:51:46.767229 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 20, length 64                         
10:51:46.767253 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 20, length 64
10:51:47.767360 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 21, length 64
10:51:47.767384 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 21, length 64
10:51:48.767451 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 22, length 64
10:51:48.767475 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 22, length 64
10:51:49.767591 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 23, length 64

without -e

listening on eth1, link-type EN10MB (Ethernet), snapshot length 262144 bytes
10:52:40.775534 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 74, length 64
10:52:40.775559 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 74, length 64
10:52:41.775635 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 75, length 64
10:52:41.775660 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 75, length 64
10:52:41.850588 ARP, Request who-has 10.5.1.2 tell 10.5.1.1, length 28
10:52:41.850603 ARP, Reply 10.5.1.2 is-at 00:16:3e:00:00:02 (oui Unknown), length 28
10:52:42.775751 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 76, length 64
10:52:42.775774 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 76, length 64
10:52:43.775955 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 77, length 64
10:52:43.775984 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 77, length 64
10:52:44.776094 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 78, length 64
10:52:44.776119 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 78, length 64
10:52:45.776221 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 79, length 64
10:52:45.776246 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 79, length

主要工具:ip

ip 是 IPRoute2 工具集中最常用的命令,能够管理和配置 IP 地址、路由、链路等多种网络参数。与旧版的 ifconfigroute 命令相比,ip 更加灵活和强大。

ip 命令的常见用法

  1. 查看网络接口

    ip link show
    

    显示所有网络接口及其状态,类似于 ifconfig

  2. 启用或禁用网络接口

    sudo ip link set dev eth0 up    # 启用接口
    sudo ip link set dev eth0 down  # 禁用接口
    
  3. 添加/删除 IP 地址

    sudo ip address add 192.168.1.10/24 dev eth0  # 为 eth0 接口添加 IP 地址
    sudo ip address del 192.168.1.10/24 dev eth0  # 从 eth0 接口删除 IP 地址
    
  4. 显示路由表

    ip route show
    

    显示当前的路由表,类似于 route 命令。

  5. 添加/删除路由

    sudo ip route add 192.168.1.0/24 via 192.168.1.1  # 添加路由条目
    sudo ip route del 192.168.1.0/24                 # 删除路由条目
    
  6. 查看 ARP 表

    ip neighbor show
    

    显示 ARP 表,类似于 arp -a