156 lines
7.8 KiB
Markdown
156 lines
7.8 KiB
Markdown
## router table
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| device | eth | ip |
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| ------- | ---- | ----------- |
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| PC1 | eth1 | 10.5.0.2/24 |
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| PC2 | eth1 | 10.5.1.2/24 |
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| router1 | eth1 | 10.5.0.1/24 |
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| router2 | eth1 | 10.5.1.1/24 |
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router -> router
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```
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sender # sender eth # receiver # receiver eth # losses #
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1 2 2 2 20
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1 3 3 2 20
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1 4 4 1 0
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2 2 1 2 20
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2 3 3 3 0
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2 4 4 2 0
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3 2 1 3 0
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3 3 2 3 0
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3 4 4 3 0
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4 1 1 4 0
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4 2 2 4 0
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4 3 3 4 0
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```
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router -> pc
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```
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sender # sender eth # receiver # receiver eth # losses # │
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1 1 1 1 0 │
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2 1 1 1 0 │
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2 1 2 1 0 │
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2 1 3 1 0 │
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3 1 3 1 0
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```
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pc->pc
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```
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sender # sender eth # receiver # receiver eth # losses #
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2 1 1 1 0
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2 1 3 1 0
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```
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pc->router
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```
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sender # sender eth # receiver # receiver eth # losses #
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2 1 2 1 0
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3 1 3 1 0
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```
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## Tcpdump output
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with -e
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```
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listening on eth1, link-type EN10MB (Ethernet), snapshot length 262144 bytes
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10:51:44.767031 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 18, length 64
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10:51:44.767055 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 18, length 64
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10:51:45.767125 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 19, length 64
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10:51:45.767160 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
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), 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
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), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 20, length 64
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10:51:46.767253 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 20, length 64
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10:51:47.767360 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 21, length 64
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10:51:47.767384 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 21, length 64
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10:51:48.767451 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 22, length 64
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10:51:48.767475 00:16:3e:00:00:02 (oui Unknown) > 00:16:3e:00:00:08 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 22, length 64
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10:51:49.767591 00:16:3e:00:00:08 (oui Unknown) > 00:16:3e:00:00:02 (oui Unknown), ethertype IPv4 (0x0800
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), length 98: 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 23, length 64
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```
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without -e
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```
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listening on eth1, link-type EN10MB (Ethernet), snapshot length 262144 bytes
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10:52:40.775534 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 74, length 64
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10:52:40.775559 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 74, length 64
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10:52:41.775635 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 75, length 64
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10:52:41.775660 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 75, length 64
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10:52:41.850588 ARP, Request who-has 10.5.1.2 tell 10.5.1.1, length 28
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10:52:41.850603 ARP, Reply 10.5.1.2 is-at 00:16:3e:00:00:02 (oui Unknown), length 28
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10:52:42.775751 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 76, length 64
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10:52:42.775774 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 76, length 64
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10:52:43.775955 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 77, length 64
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10:52:43.775984 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 77, length 64
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10:52:44.776094 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 78, length 64
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10:52:44.776119 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 78, length 64
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10:52:45.776221 IP 10.5.1.1 > 10.5.1.2: ICMP echo request, id 4813, seq 79, length 64
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10:52:45.776246 IP 10.5.1.2 > 10.5.1.1: ICMP echo reply, id 4813, seq 79, length
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```
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### 主要工具：`ip`
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**`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 `ifconfig` 和 `route` 命令相比，`ip` 更加灵活和强大。
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### **`ip` 命令的常见用法**
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1. **查看网络接口**：
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```bash
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ip link show
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```
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显示所有网络接口及其状态，类似于 `ifconfig`。
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2. **启用或禁用网络接口**：
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```bash
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sudo ip link set dev eth0 up # 启用接口
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sudo ip link set dev eth0 down # 禁用接口
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```
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3. **添加/删除 IP 地址**：
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```bash
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sudo ip address add 192.168.1.10/24 dev eth0 # 为 eth0 接口添加 IP 地址
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sudo ip address del 192.168.1.10/24 dev eth0 # 从 eth0 接口删除 IP 地址
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```
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4. **显示路由表**：
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```bash
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ip route show
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```
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显示当前的路由表，类似于 `route` 命令。
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5. **添加/删除路由**：
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```bash
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sudo ip route add 192.168.1.0/24 via 192.168.1.1 # 添加路由条目
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sudo ip route del 192.168.1.0/24 # 删除路由条目
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```
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6. **查看 ARP 表**：
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```bash
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ip neighbor show
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```
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显示 ARP 表，类似于 `arp -a`。
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