????4??TCPDUMP——???????????????

????tcpdump????ù?????????——??????????????????????????????????????????????????????????????????TCP/IP??????????????????????浽?????????С?tcpdump???????????????Linux???а?????á?

    # tcpdump -i eth0 
    tcpdump: verbose output suppressed?? use -v or -vv for full protocol decode 
    listening on eth0?? link-type EN10MB (Ethernet)?? capture size 96 bytes 
    22:08:59.617628 IP tecmint.com.ssh > 115.113.134.3.static-mumbai.vsnl.net.in.28472: P 2532133365:2532133481(116) ack 3561562349 win 9648 
    22:09:07.653466 IP tecmint.com.ssh > 115.113.134.3.static-mumbai.vsnl.net.in.28472: P 116:232(116) ack 1 win 9648 
    22:08:59.617916 IP 115.113.134.3.static-mumbai.vsnl.net.in.28472 > tecmint.com.ssh: . ack 116 win 64347

????5??NETSTAT——???????

????netstat??????????й??????????????????????????????????????????????????????????м?????????????????????????й????????????????

    # netstat -a | more 
    Active Internet connections (servers and established) 
    Proto Recv-Q Send-Q Local Address               Foreign Address             State 
    tcp        0      0 *:mysql                     *:*                         LISTEN 
    tcp        0      0 *:sunrpc                    *:*                         LISTEN 
    tcp        0      0 *:realm-rusd                *:*                         LISTEN 
    tcp        0      0 *:ftp                       *:*                         LISTEN 
    tcp        0      0 localhost.localdomain:ipp   *:*                         LISTEN 
    tcp        0      0 localhost.localdomain:smtp  *:*                         LISTEN 
    tcp        0      0 localhost.localdomain:smtp  localhost.localdomain:42709 TIME_WAIT 
    tcp        0      0 localhost.localdomain:smtp  localhost.localdomain:42710 TIME_WAIT 
    tcp        0      0 *:http                      *:*                         LISTEN 
    tcp        0      0 *:ssh                       *:*                         LISTEN 
    tcp        0      0 *:https                     *:*

????6??HTOP——Linux??????

????Htop???????????????????????Linux???????????????????top????????????????????????????????????????????????????????????????????Htop???????????????????????????YUM??????????????Linux?????????????á?