AT-WR4500 Series - IEEE 802.11abgh Outdoor Wireless Routers
129
RouterOS v3 Configuration and User Guide
6.2
DNS Client and Cache
Document revision:
1.2 (Fri Ap r 15 17:37:43 GMT 2005)
Applies to:
V2.9
6.2.1
General Information
Summary
DNS cache is used to minimize DNS requests to an external DNS server as well as to minimize DNS
resolution time. This is a simple recursive DNS server with local items.
Specifications
Packages required:
system
License required:
Level1
Submenu level:
/ip dns
Standards and Technologies:
DNS
Hardware usage:
Not significant
Related Topics
IP and Routing
Description
The RouterOS router with DNS cache feature enabled can be set as a primary DNS server for any DNS-
compliant clients. Moreover, RouterOS router can be specified as a primary DNS server under its dhcp-
server settings. When the DNS cache is enabled, the RouterOS router responds to DNS TCP and UDP
requests on port 53.
Additional Resources
http://www.ietf.org/rfc/rfc1035.txt?number=1035
http://www.freesoft.org/CIE/Course/Section2/3.htm
http://www.networksorcery.com/enp/protocol/dns.htm
http://en.wikipedia.org/wiki/Domain_Name_System
6.3
DNS Cache Setup
Submenu level:
/ip dns
Description
DNS facility is used to provide domain name resolution for router itself as well as for the clients
connected to it..
Property Description
allow-remote-requests
(yes | no) - specifies whether to allow network requests
cache-max-ttl
(
time
; default:
1w
) - specifies maximum time-to-live for cahce records. In other words,
cache records will expire after
cache-max-ttl
time.
cache-size
(
integer
: 512..10240; default:
2048KiB
) - specifies the size of DNS cache in KiB
cache-used
(
read-only: integer
) - displays the currently used cache size in KiB
primary-dns
(
IP address
; default:
0.0.0.0
) - primary DNS server
secondary-dns
(
IP address
; default:
0.0.0.0
) - secondary DNS server
If the property
use-peer-dns
under
/ip dhcp-client
is set to
yes
then
primary-dns
under
/ip dns
will change to a DNS address given by DHCP Server.