Tag: DNS

  • How to configure Cisco Router as Authoritative DNS Server

    While we saw here how to setup a Cisco Router as a Caching/Forwarding DNS Server. We can now look at how to make your Cisco Router as an Authoritative DNS server. When configured as an authoritative name server for its own local host table, the router listens on port 53 for DNS queries and then answers DNS queries using the permanent and cached entries in its own host table.

    Careful consideration has to be given as this can consume considerable amount of resources like CPU cycles on the Cisco Router. If you are a small network and realise your Cisco ROuter is under utilised then there is a good business case to turn your router into a DNS server.

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  • Configure Cisco Router as Caching/Forwarding DNS Server

    A Cisco Router running Cisco IOS can function as a Caching or Forwarding DNS Server which answers to DNS queries from clients either from its host table or cache or forward it to a DNS server which can respond to the query.

    This feature can come in handy in small network environments where the router can act as a Caching DNS server forwarding queries to the ISPs DNS servers or infact any external DNS servers. Also, makes sense using on under utilized DNS servers.

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  • How to configure DHCP server on Cisco Routers and switches with Cisco IOS

    DHCP, Dynamic Host Configuration Protocol  is the protocol used by network devices like a PC or a printer (DHCP clients) to obtain IP Address, Default Gateway, Domain Name, DNS Servers, NetBIOS servers and more that helps the device to work properly in an IP Network.

    While in an ideal scenario, most if not all organisations run the DHCP server on  a Windows server or a Linux/Unix server. While this is justfiable in bigger corporate and enterprise networks, a smaller network like a branch office can be supported by a local Router, Switch or a Firewall can run a DHCP server without the need of an additional server hardware to run DHCP. Most of the routers, firewalls and some switches do have a DHCP server builtin. Most of the new Cisco Routers and Switches running Cisco IOS can run a DHCP server.

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  • Dnsmasq – Opensource DNS Server Forwarder & DHCP Server

    Dnsmasq is an opensource light-weight,easy to configure and administer DNS and a DHCP Server. Dnsmasq is ideally suitable for smaller networks like Small Office and Home Office networks (SOHO) and branch office networks. Dnsmasq can be run on old PC and is very easy to configure and administer. Dnsmasq is seen to support upto 1000 nodes on a network.

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  • HowTo: Add or Edit the DNS servers in Sun Solaris

    Domain Name Service (DNS) is a system which translates the meaningful Hostnames and Domain Names into valid IP Addresses. A DNS Client or a Resolver is a host or a network device which queries the DNS servers for various resource records like the IP Address for a host like a Mail Server.

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  • Alert: DNS L.ROOR-SERVERS.NET IP Address has changed

    From the 1st November, the IP address for the L Root servers (L.ROOR-SERVERS.NET) for DNS lookups has changed. The new IP Address will be

    199.7.83.42

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  • Add a SPF Resource Record in Windows 2003 DNS

    The Sender ID Framework is a new authentication protocol that can be used to counter spoofing by people who send unsolicited commercial e-mail messages (spam). Spoofing is the practice of forging a sender's address on e-mail messages. Spoofing misleads e-mail recipients and makes them read and respond to deceptive e-mail messages. To safeguard Internet domain names, and to help e-mail recipients identify junk e-mail messages and phishing scams more effectively, administrators can publish SPF records in the public DNS.

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