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Showing posts from September, 2011

Speaking of filters - my segment of the BT Tower webcast

As a follow up to my post-live webcast blogpost , here is just my segment from the webcast where I talk about IPv6. Enjoy!

Handy AAAA filter in BIND 9.8

The ISC introduced a pair of new configuration file options in BIND 9.8 to enable administrators to easily filter who may receive AAAA record type responses even if valid responses exist. For example, clients on subnets that do not have IPv6 network access can be excluded from receiving affirmative answers for AAAA queries. This feature provides simpler administration than the alternative mechanism using views. The first option, filter-aaaa-on-v4,defines whether the server will return AAAA records to certain clients. Such clients are defined by the address match list parameter of the second option, filter-aaaa. Note that BIND must be compiled with the --enable-filter-aaaa option on the configure command line to enable AAAA filtering. The syntax of these options is as follows: filter-aaaa-on-v4 (yes | no | break-dnssec) ; filter-aaaa {addr_match_list;} ; The filter-aaaa option identifies the address match list for which the filter-aaaa-on-v4 option is to be applied as described

Dual stack host default address selection

As many organizations ponder IPv6 deployment, the most popular approach will be dual-stack deployment according to a recent survey . This approach entails activating IPv4 and IPv6 address types and assigning corresponding addresses by defined means such as manual, DHCP or auto-configuration for a given device's interface(s). All major host operating systems (OSs) support IPv4 and IPv6 and in some cases auto-configure IPv6 addresses by default. When an application seeks to communicate with a remote host given its hostname, the application calls the getaddrinfo() sockets API call. This API call triggers one or more DNS lookups (though other forms of name resolution could be used) with the query name set to the hostname passed in the getaddrinfo() call, the query class set to Internet and the query type set to A and AAAA on successive DNS queries. So given a host with both IPv4 and IPv6 interface addresses and destination host name resolution yielding both IPv4 and IPv6 addresses, wh

Planned Obsolescence in the IPAM Industry

Many products become obsolete or passe over time due to the availability of newer products with technology improvements or of more attractive replacement products, or even due to intangible factors such as social fads or trends. I'd term these natural or unplanned obsolescence. But planned obsolescence is a scheme where a product is consciously designed, manufactured or offered with a limited lifetime. The motivation is obvious: the product bought this year will become obsolete within x years, so the customer will need to re-purchase the product at that time. Perhaps you've recently heard something like this from your IPAM (aka DDI) vendor: "Sorry that version of software doesn't run on that version of hardware." Or "that version of product has expired as has your support. I guess you'll have to repurchase everything!" While this may be sound strategy for growing top-line revenue as every sale today will be repeated in x years, it's not n