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HP OpenVMS Systems Documentation |
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Compaq TCP/IP Services for OpenVMS
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The interfaces and ports from which the server answers queries can be specified using the listen-on options. Table C-10 describes the listen-on options.
| Option | Description |
|---|---|
| listen-on |
Specifies the port for listening for queries sent using IPv4 addresses.
The listen-on option takes an optional port number and an address_match_list . The server listens on all interfaces allowed by the address match list. If a port is not specified, port 53 is used. Multiple
listen-on
statements are allowed. For example:
These statements enable the name server on port 53 for the IP address 5.6.7.8, and on port 1234 of an address on the machine in net 1.2 that is not 1.2.3.4. If the listen-on option is not specified, the server listens on port 53 on all interfaces. |
| listen-on-v6 |
Specifies the ports on which the server listens for incoming queries
sent using IPv6. The server does not bind a separate socket to each
IPv6 interface address as it does for IPv4. Instead, it always listens
on the IPv6 wildcard address. Therefore, the values allowed for the
address_match_list
argument to the
listen-on-v6
option are:
Multiple
listen-on-v6
options can be used to listen on multiple ports. For example:
To make the server not listen on any IPv6 address, specify the
following:
If the listen-on-v6 option is not specified, the server does not listen on any IPv6 address. |
If the server does not know the answer to a question, it queries other name servers. The query address options allow you to specify the address and port for these queries.
Table C-11 describes the query address options.
| Option | Description |
|---|---|
| query-source |
Specifies the IPv4 address and port used for such queries. If the
address is a wildcard character or is omitted, a wildcard IP address
(INADDR_ANY) is used. If the port is a wildcard character or is
omitted, a random unprivileged port is used. The default is:
query-source address * port *; |
| query-source-v6 |
Specifies the IPv6 address and port used for such queries. The default
is:
query-source-v6 address * port * |
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.
C.5.3.6.6 Zone Transfer Options
BIND includes mechanisms to facilitate zone transfers and to limit the amount of load that transfers place on the system. Table C-12 describes the zone transfer options.
| Option | Description |
|---|---|
| also-notify | Defines a global list of IP addresses of name servers that are also sent NOTIFY messages whenever a fresh copy of the zone is loaded, in addition to the servers listed in the zone's NS records. This helps to ensure that copies of the zones will quickly converge on stealth servers. If an also-notify list is given in a zone statement, that list overrides the also-notify options in the options statement. When a zone notify statement is set to NO, the IP addresses in the global also-notify list are not sent NOTIFY messages for that zone. The default is the empty list (no global notification list). |
| max-transfer-time-in | Inbound zone transfers running longer than this many minutes are terminated. The default is 120 minutes. |
| max-transfer-idle-in | Inbound zone transfers making no progress in this many minutes are terminated. The default is 60 minutes. |
| max-transfer-time-out | Outbound zone transfers running longer than this many minutes are terminated. The default is 120 minutes. |
| max-transfer-idle-out | Outbound zone transfers making no progress in this many minutes are terminated. The default is 60 minutes. |
| serial-query-rate | Slave servers periodically query master servers to find out whether zone serial numbers have changed. Each such query uses a minute amount of the slave server's network bandwidth. To limit the amount of bandwidth used, BIND 9 limits the rate at which queries are sent. The value of the serial-query-rate option is the maximum number of queries sent per second. The default is 20. |
| serial-queries | In BIND 8, this option set the maximum number of concurrent serial number queries allowed to be outstanding at any given time. BIND 9 does not limit the number of outstanding serial queries and ignores the serial-queries option. Instead, it limits the rate at which the queries are sent as defined by the serial-query-rate option. |
| transfer-format |
Specifies whether zone transfers are sent using the one-answer format
or the many-answers format. The
transfer-format
option is used on the master server to determine which format it sends.
When set to
one-answer
, it uses one DNS message per resource record transferred. When set to
many-answers
, it packs as many resource records as possible into a message.
many-answers
is more efficient, but it is supported only by relatively new slave
servers, such as BIND Version 9, BIND Version 8, and later versions of
BIND Version 4. The default is
many-answers
.
The transfer-format option can be overridden on a per-server basis by using the server statement. |
| transfers-in |
Specifies the maximum number of inbound zone transfers that can be
running concurrently. The default value is 10. Increasing the
transfers-in
value might speed up the convergenc
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