IP Address Management (IPAM) topics related to IPv4, IPv6, DHCP, DNS, DNS security including DNSSEC, cloud IPAM, and related technologies with a perspective on effectively managing these critical networking functions.
Speaking of filters - my segment of the BT Tower webcast
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As a follow up to my post-live webcast blogpost, here is just my segment from the webcast where I talk about IPv6. Enjoy!
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
We all know how critical DHCP/DNS/IPAM (DDI) services are. Your network cannot function without them. But like most foundational elements of anything, they are certainly not glamorous...like good luck finding a home designer who specializes in home foundations. I would not be shocked should HGTV pass on my brilliant concept for a foundation building show. I suppose most people would find a show detailing footing depths and concrete pouring techniques rather boring. Nevertheless, there are countless shows for redesigning and remodeling homes. On most episodes the foundation is out of sight, out of mind. If it's stable, no one wants to pay it attention, they just expect it to keep doing its job, supporting the structure. Once in a while a foundational issue is brought up that unexpectedly threatens to raise the budget to heighten the drama. All work stops until the issue is addressed. And you'll notice that the owner never denies paying the extra amount to fix the issue.
BIND 9.8.0 introduced a new dns64 option statement that can be configured within the server named.conf options block or within a view options block. Recall from a prior post that DNS64 configures a recursive DNS server to issue A record queries on behalf of a client requesting AAAA records, then appends the returned IPv4 address to a defined IPv6 prefix. This manufactured IPv6 address enables the querying host to connect to a NAT64 gateway which will terminate the IPv6 connection from the client and map it to an outbound IPv4 connection to the appended IPv4 address, completing the connection! Whew! BIND offers a number of useful parameters within the dns64 statement to control this process. The statement syntax is: dns64 IPv6_prefix { [clients {address_match_list };] [mapped {address_match_list };] [exclude {address_match_list };] [suffix IPv6_addr;] [recursive-only (yes|no);] [break-dnssec (yes|no);] }; The IPv6_prefix parameter is the prefix to which returned
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