Allied Telesis AT-AR300 manual Domain Name Server Enhancements, DNS Caching

Page 7

Software Release 2.3.1

7

Figure 2: Example output from the SHOW INTERFACE command for a specific interface.

Interface

bri0

ifIndex

3

ifMTU

1712

ifSpeed

144000

ifAdminStatus

Up

ifOperStatus

Swapped out

ifLinkUpDownTrapEnable...

Disabled

TrapLimit

20

Interface Counters

 

 

 

ifInOctets

52190

ifOutOctets

52190

ifInUcastPkts

3070

ifOutUcastPkts

3071

ifInNUcastPkts

0

ifOutNUcastPkts

0

ifInDiscards

0

ifOutDiscards

0

ifInErrors

0

ifOutErrors

0

Table 1: New parameter displayed in the output of the SHOW INTERFACE command.

Parameter

Meaning

 

 

ifOperStatus

The current operational state of the interface; one of “Up”,

 

”Down”, “Testing”, or “Swapped Out”.

 

 

Domain Name Server Enhancements

Software Release 2.3.1 includes two enhancements to Domain Name Server (DNS) functionality:

The router can now store recently obtained DNS information in a cache.

The router can now be configured to use a range of DNS servers. Server selection is based on the host name that is being resolved.

DNS Caching

DNS caching allows the router to store recently requested domain or host addresses so they can be quickly retrieved if an identical DNS request is received. DNS caching reduces traffic on the Internet and improves performance for both DNS and DNS relay under heavy usage. The DNS cache is of a limited size, and times out entries after a specified period of up to 60 minutes.

When a domain or host is requested, the cache is searched for a matching entry. If a match is found, a response is sent to the requesting PC or host. If a matching entry is not found, a request will be sent to a remote server.

First, add a DNS server to the list of DNS servers used to resolve host names into IP addresses, using the command:

ADD IP DNS [DOMAIN={ANYdomain-name}] {INTERFACE=interface

PRIMARY=ipadd [SECONDARY=ipadd]}

Software Release 2.3.1 C613-10325-00 REV B

Image 7
Contents Software Release Hardware Platforms IntroductionRapier i Series Hot Swapping Network Service Modules Hot swap an NSM out of an NSM bay Software Features NSM Hot Swap Software Support Example output from the Show Interface commandDNS Caching Domain Name Server EnhancementsServer Selection Telnet Server Port Number Automatic Nameserver ConfigurationTriggers for Ethernet Interfaces Enco Channels IP Security IPsec Source Interface Enhancements Ospf on Demand Isdn Interface-based NAT Paladin Firewall EnhancementsRule-based NAT Time Limited Rules New Command SyntaxRelease Note Software Release Required parameters for Firewall NAT rules Parameters Web Redirection with Reverse NAT RulesFirewall and IPsec Tunnel Further ExamplesStandard NAT Show Output Paladin Firewall Http Application Gateway ProxyHttp Filters Firewall Http Proxies and Firewall PoliciesADD Firewall POLICY=zone1 HTTPFILTER=banned.htp Http Cookies Show Firewall Policy Firewall Policy DebuggingHttp Proxy Filter File Vrrp Port MonitoringWhere Stepvalue is a decimal number in the range 1 to Border Gateway Protocol 4 BGP-4 Internet Protocol IP IP and Interface CountersTo reset IP interfaces, use the command Example output from the Show IP COUNTER=INTERFACE command Example output from the Show IP COUNTER=SNMP command Telephony PBX Functionality Errata Telnet Server Bandwidth LimitingEnable Telnet Server InstallationRelease Note