nc udp

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nc命令测试udp端口联通性


安装

1. yum install -y nc

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1. [root@vm2 ~]# nc -h
   
2. Ncat 7.50 ( https://nmap.org/ncat )
   
3. Usage: ncat [options] [hostname] [port]
   
4. 
   
5. Options taking a time assume seconds. Append 'ms' for milliseconds,
   
6. 's' for seconds, 'm' for minutes, or 'h' for hours (e.g. 500ms).
   
7.   -4                         Use IPv4 only
   
8.   -6                         Use IPv6 only
   
9.   -U, --unixsock             Use Unix domain sockets only
   
10.   -C, --crlf                 Use CRLF for EOL sequence
    
11.   -c, --sh-exec <command>    Executes the given command via /bin/sh
    
12.   -e, --exec <command>       Executes the given command
    
13.       --lua-exec <filename>  Executes the given Lua script
    
14.   -g hop1[,hop2,...]         Loose source routing hop points (8 max)
    
15.   -G <n>                     Loose source routing hop pointer (4, 8, 12, ...)
    
16.   -m, --max-conns <n>        Maximum <n> simultaneous connections
    
17.   -h, --help                 Display this help screen
    
18.   -d, --delay <time>         Wait between read/writes
    
19.   -o, --output <filename>    Dump session data to a file
    
20.   -x, --hex-dump <filename>  Dump session data as hex to a file
    
21.   -i, --idle-timeout <time>  Idle read/write timeout
    
22.   -p, --source-port port     Specify source port to use
    
23.   -s, --source addr          Specify source address to use (doesn't affect -l)
    
24.   -l, --listen               Bind and listen for incoming connections
    
25.   -k, --keep-open            Accept multiple connections in listen mode
    
26.   -n, --nodns                Do not resolve hostnames via DNS
    
27.   -t, --telnet               Answer Telnet negotiations
    
28.   -u, --udp                  Use UDP instead of default TCP
    
29.       --sctp                 Use SCTP instead of default TCP
    
30.   -v, --verbose              Set verbosity level (can be used several times)
    
31.   -w, --wait <time>          Connect timeout
    
32.   -z                         Zero-I/O mode, report connection status only
    
33.       --append-output        Append rather than clobber specified output files
    
34.       --send-only            Only send data, ignoring received; quit on EOF
    
35.       --recv-only            Only receive data, never send anything
    
36.       --allow                Allow only given hosts to connect to Ncat
    
37.       --allowfile            A file of hosts allowed to connect to Ncat
    
38.       --deny                 Deny given hosts from connecting to Ncat
    
39.       --denyfile             A file of hosts denied from connecting to Ncat
    
40.       --broker               Enable Ncat's connection brokering mode
    
41.       --chat                 Start a simple Ncat chat server
    
42.       --proxy <addr[:port]>  Specify address of host to proxy through
    
43.       --proxy-type <type>    Specify proxy type ("http" or "socks4" or "socks5")
    
44.       --proxy-auth <auth>    Authenticate with HTTP or SOCKS proxy server
    
45.       --ssl                  Connect or listen with SSL
    
46.       --ssl-cert             Specify SSL certificate file (PEM) for listening
    
47.       --ssl-key              Specify SSL private key (PEM) for listening
    
48.       --ssl-verify           Verify trust and domain name of certificates
    
49.       --ssl-trustfile        PEM file containing trusted SSL certificates
    
50.       --ssl-ciphers          Cipherlist containing SSL ciphers to use
    
51.       --version              Display Ncat's version information and exit
    

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1. [root@vm2 ~]# nc -zvu 192.168.56.1 123
   
2. Ncat: Version 7.50 ( https://nmap.org/ncat )
   
3. Ncat: Connected to 192.168.56.1:123.
   
4. Ncat: UDP packet sent successfully
   
5. Ncat: 1 bytes sent, 0 bytes received in 2.01 seconds.

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1. [root@vm2 ~]# ntpdate 192.168.56.1
   
2. 2 Aug 11:14:06 ntpdate[5946]: step time server 192.168.56.1 offset 506468.928271 sec
   

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