named udp random port - not mentioned in the configuration file.

[Kevin Darcy]

As per the BIND 9 ARM:


      6.2.16.6. Query Address

If the server doesn't know the answer to a question, it will query other 
name servers. *query-source* specifies the address and port used for 
such queries. For queries sent over IPv6, there is a separate 
*query-source-v6* option. If *address* is *** or is omitted, a wildcard 
IP address (*INADDR_ANY*) will be used. If *port* is *** or is omitted, 
a random unprivileged port will be used, *avoid-v4-udp-ports* and 
*avoid-v6-udp-ports* can be used to prevent named from selecting certain 
ports. The defaults are

query-source address * port *;
query-source-v6 address * port *;

    *Note: *The address specified in the *query-source* option is used
    for both UDP and TCP queries, but the port applies only to UDP
    queries. TCP queries always use a random unprivileged port.

    *Note: *See also *transfer-source* and *notify-source*.

                                                                      
                                     - Kevin


Fabiano Silos Reis wrote:

> 
>Hi,
>
> 
>
>Do someone know for what a random udp port is used? AFAIK my named
>process is running with rndc control port (953) and 53(tcp/udp), except
>for this random port that changes each time I restart named.
>
> 
>
>$ lsof -i UDP:32768
>
>COMMAND PID USER   FD   TYPE DEVICE SIZE NODE NAME
>
>named   402 named   24u  IPv4   2814       UDP *:32768
>
> 
>
>$ netstat -nl
>
>Active Internet connections (only servers)
>
>Proto Recv-Q Send-Q Local Address           Foreign Address
>State
>
>tcp        0      0 127.0.0.1:53            0.0.0.0:*
>LISTEN
>
>tcp        0      0 127.0.0.1:953           0.0.0.0:*
>LISTEN
>
>udp        0      0 0.0.0.0:32768           0.0.0.0:*
>
>udp        0      0 127.0.0.1:53            0.0.0.0:*
>
> 
>
>Thanks!
>
> 
>
>Fabiano
>
>
>
>
>
>
>  
>