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AT-WR4500 Series - IEEE 802.11abgh Outdoor Wireless Routers 129
RouterOS v3 Configuration and User Guide
6.2 DNS Client and Cache
Document revisi on: 1.2 (Fri Apr 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.