Configuring TCP/IP Networking manually with the command line
Категория: Securing and Optimizing
Kernel IP routing table
| Destination | Gateway | Genmask | Flags | Metric | Ref | Use Iface |
| 208.164.186.2 | 0.0.0.0 | 255.255.255.255 | UH | 0 | 0 | OethO |
| 208.164.186.0 | 208.164.186.2 | 255.255.255.0 | UG | 0 | 0 | OethO |
| 208.164.186.0 | 0.0.0.0 | 255.255.255.0 | U | 0 | 0 | OethO |
| 127.0.0.0 | 0.0.0.0 | 255.0.0.0 | U | 0 | 0 | Olo |
• To check the status of the interfaces quickly, use the netstat -i command, as follows: [root@deep /]# netstat -i
The output should look something like this:
| Kernel | Interface table | |||||||||
| Iface | MTU | Met | RX-OK | RX-ERR | RX-DRP | RX-OVR | TX-OK | TX-ERR | TX-DRP | TX-OVR Fig |
| ethO | 1500 | 0 | 4236 | 0 | 0 | 0 | 3700 | 0 | 0 | 0 BRU |
| lo | 3924 | 0 | 13300 | 0 | 0 | 0 | 13300 | 0 | 0 | 0 LRU |
| pppO | 1500 | 0 | 14 | 1 | 0 | 0 | 16 | 0 | 0 | 0 PRU |
Another useful netstat option is -t, which shows all active TCP connections. Following is a typical result of netstat -t:
• To shows all active TCP connections, use the command: [root@deep /]# netstat -t
The output should look something like this:
| Active | Internet connections (w/o servers) | ||||
| Proto | Recv-Q | Send-Q | Local Address | Foreign Address | State |
| Tcp | 0 | 0 | deep.openar:netbios-ssn | gate.openna.com:1045 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1032 | localhost:1033 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1033 | localhost:1032 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1030 | localhost:1034 | ESTABLISHED |
| Tcp | 0 | 0 | localhost:1031 | localhost:1030 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1028 | localhost:1029 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1029 | localhost:1028 | ESTABLISHED |
| Tcp | 0 | 0 | localhost:1026 | localhost:1027 | ESTABLISHED |
| Tcp | 0 | 0 | localhost:1027 | localhost:1026 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1024 | localhost:1025 | ESTABLISHED |
| Tcp | 0 | 0 | local host: 1025 | localhost:1024 | ESTABLISHED |
• To shows all active and listen TCP connections, use the command: [root@deep /]# netstat -vat
The output should look something like this:
| Active Internet connections (servers and | established) | |||
| Proto | Recv-Q Send-Q Local Address | Foreign Address State | ||
| tcp | 0 | 0 deep.openna.co:domain | *.* | LISTEN |
| tcp | 0 | 0 localhost:domain | *.* | LISTEN |
| tcp | 0 | 0 deep.openna.com:ssh | gate.openna.com: | 1682 ESTABLISHED |
| tcp | 0 | 0 *:webcache | *.* | LISTEN |
| tcp | 0 | 0 deep.openar:netbios-ssn | *.* | LISTEN |
| tcp | 0 | 0 localhost:netbios-ssn | *.* | LISTEN |
| tcp | 0 | 0 localhost:1032 | localhost:1033 | ESTABLISHED |
| tcp | 0 | 0 localhost:1033 | localhost:1032 | ESTABLISHED |
| tcp | 0 | 0 localhost:1030 | localhost:1031 | ESTABLISHED |
| tcp | 0 | 0 localhost:1031 | localhost:1030 | ESTABLISHED |
| tcp | 0 | 0 localhost:1028 | localhost:1029 | ESTABLISHED |
| tcp | 0 | 0 localhost:1029 | localhost:1028 | ESTABLISHED |
| tcp | 0 | 0 localhost:1026 | localhost:1027 | ESTABLISHED |
| tcp | 0 | 0 localhost:1027 | localhost:1026 | ESTABLISHED |
| tcp | 0 | 0 localhost:1024 | localhost:1025 | ESTABLISHED |
| tcp | 0 | 0 localhost:1025 | localhost:1024 | ESTABLISHED |
| tcp | 0 | 0 deep.openna.com:www | *.* | LISTEN |
| tcp | 0 | 0 deep.openna.com:https | *.* | LISTEN |
| tcp | 0 | 0 *:389 | *.* | LISTEN |
| tcp | 0 | 0 *:ssh | *.* | LISTEN |