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Differences between version 10 and revision by previous author of ResourceRecord.

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Newer page: version 10 Last edited on Sunday, November 28, 2004 11:38:44 am by AristotlePagaltzis Revert
Older page: version 7 Last edited on Saturday, November 27, 2004 2:12:26 am by GoogleSite Revert
@@ -1,176 +1,126 @@
-The smallest unit of queriable data in the [DNS], commonly referred to by its [Acronym | WLUG:Acronym] [RR] . 
+The smallest unit of queriable data in the [DNS]. Each ResourceRecord has a type which gives particular meaning to its payload . These types include:  
  
-Each ResourceRecord has a type which gives particular meaning to its payload . These types include : 
+__<tt>A</tt>__:  
+ Short for "address" . An [IPv4] address. Specified in RFC :1035. Example:  
+ <verbatim>  
+ foo.example.org A 1.2.3.4  
+ </verbatim>  
  
-* [ A] , [AAAA] and [A6]  
-* [CNAME]  
-* [DNAME]  
-* [LOC] (to find the [GPS] location of a machine or site)  
-* [MX] (to find an [SMTP ] server for a domain)  
-* [NS] ( to find a NameServer for domain)  
-* [PTR] (for doing a ReverseLookup)  
-* [SOA]  
-* TXT  
+__<tt>AAAA</tt>__:  
+ Like <tt> A</tt> , but stores an [IPv6 ] address; to be obsoleted by <tt>A6</tt>. Specified in RFC:1886. Example:  
+ <verbatim>  
+ foo.example.org AAAA 2002:c000:0200::1  
+ </verbatim>  
  
-A more comprehensive list of ResourceRecord~s is at: http ://www .dns .net/dnsrd/rr .html  
+__<tt>A6</tt>__ :  
+ Supposed to obsolete <tt>AAAA< /tt> for [IPv6] addresses.  
+ Many people continue using <tt>AAAA< /tt> due to the complexity of A6, see [AAAAvsA6] .  
+ Specified in RFC:2874 . Example:  
+ <verbatim>  
+ $ORIGIN X .EXAMPLE.  
+ N A6 64 ::1234:5678:9ABC:DEF0 SN-1.IP6  
+ SN-1.IP6 A6 48 :::1:: IP6  
+ IP6 A6 48 ::0 CUST-X.IP6.A.NET.  
+ IP6 A6 48 ::0 CUST-X.IP6.B.NET.  
+ </verbatim>  
  
-''InNeedOfRefactor: fold all the pages for individual ResourceRecord types into this one; none of them is long, and using "an A ResourceRecord" gives __much __ better context for links than "an [A] record" , while " an [ A] [RR]" is redundant .''  
+__<tt>CNAME</tt> __:  
+ Short for Canonical Name , an alias for a hostname.  
+ Often used for well known services so that <tt>www.example.com</tt> points to <tt>arthur.example.com</tt>.  
+ Specified in RFC:1035. Example:  
+ <verbatim>  
+ www.xtra.co.nz CNAME xtra.co.nz  
+ xtra.co.nz A 202.27.184 .102  
  
-----  
-CategoryDns  
+ mail.xtra.co.nz CNAME mta.xtra.co.nz  
+ mta.xtra.co.nz A 203.96.92.132  
+ </verbatim>  
+ Some record types in [DNS] are not allowed to be <tt>CNAME</tt>s. Similar to <tt>DNAME</tt>. See the NamedNotes page for more details.  
  
-[电影|http ://www .591dy .com]  
-[免费电影|http://www .591dy .com]  
-[电影下载|http:// www.591dy .com]  
-[在线电影 |http://www.591dy .com ]  
-[影视|http:/ /www.591dy .com]  
-[免费电影下载|http: //www .591dy.com]  
+__<tt>DNAME</tt>__ :  
+ Basically a <tt>CNAME< /tt> for an entire domain . Specified in RFC:2672 . Example:  
+ <verbatim>  
+ test .meta.net.nz. IN DNAME wlug.org.nz .  
+ </verbatim>  
+ With this in place <tt> [www.test .meta.net.nz |http://www.test .meta.net.nz/ ]< /tt> resolves to <tt> www.wlug .org.nz< /tt> . 
  
-[猫沙|http://080 .google .591dy.com]  
-[猫抓板|http://079.google.591dy.com ]  
-[猫用品|http: //078.google.591dy.com]  
-[猫粮|http ://077.google.591dy.com]  
-[模具|http://076.google.591dy.com]  
-[新力净化|http://075 .google .591dy .com]  
-[空气净化行业|http://074 .google .591dy .com]  
-[洁净论坛|http://073 .google.591dy.com]  
-[洁净技术|http://072 .google .591dy .com]  
-[clean room|http://071 .google .591dy .com]  
-[无尘室|http://070 .google .591dy .com]  
-[无尘室净化设备|http://069 .google .591dy .com]  
-[风机过滤网|http://068 .google .591dy .com]  
-[有隔板空气过滤器|http://067 .google .591dy.com]  
-[铝隔板式高效率空气过滤器|http://066 .google .591dy .com]  
-[无隔板高效空气过滤器|http://065 .google .591dy .com]  
-[高效率空气过滤器|http://064 .google.591dy.com]  
-[空气过滤器|http: //063.google.591dy.com]  
-[狩猎|http://062 .google.591dy.com]  
-[头盔夜视仪|http://061.google.591dy.com]  
-[红外热成像仪|http://060.google.591dy.com]  
-[双筒夜视仪|http://059.google.591dy.com]  
-[枪械瞄准镜|http://058.google.591dy.com]  
-[微光夜视仪|http://057.google.591dy.com]  
-[夜视瞄准镜|http://056.google.591dy.com]  
-[手持夜视观察仪|http://055.google.591dy.com]  
-[药物流产|http://054.google.591dy.com]  
-[钛板|http://053.google.591dy.com]  
-[冷却塔|http://052.google.591dy.com]  
-[挖掘机|http://051.google.591dy.com]  
-[搅拌器|http://050.google.591dy.com]  
-[球磨机|http://049.google.591dy.com]  
-[离心机|http://048.google.591dy.com]  
-[会计师事务所|http://047.google.591dy.com]  
-[标签打印机|http://046.google.591dy.com]  
-[吸顶灯|http://045.google.591dy.com]  
-[反光材料|http://044.google.591dy.com]  
-[强直性脊柱炎|http://043.google.591dy.com]  
-[自动门|http://042.google.591dy.com]  
-[钢结构|http://041.google.591dy.com]  
-[尿毒症|http://040.google.591dy.com]  
-[化学清洗|http://039.google.591dy.com]  
-[工业清洗|http://038.google.591dy.com]  
-[电视墙|http://037.google.591dy.com]  
-[加密狗|http://036.google.591dy.com]  
-[过滤器|http://035.google.591dy.com]  
-[艾滋病|http://034.google.591dy.com]  
-[梅毒|http://033.google.591dy.com]  
-[尖锐湿疣|http://032.google.591dy.com]  
-[淋病|http://031.google.591dy.com]  
-[性病|http://030.google.591dy.com]  
-[电子白板|http://029.google.591dy.com]  
-[升降机|http://028.google.591dy.com]  
-[脚手架|http://027.google.591dy.com]  
-[高压水枪|http://026.google.591dy.com]  
-[吸脂|http://025.google.591dy.com]  
-[洗涤设备|http://024.google.591dy.com]  
-[桑拿设备|http://023.google.591dy.com]  
-[加湿器|http://022.google.591dy.com]  
-[防盗门|http://021.google.591dy.com]  
-[保暖内衣|http://020.google.591dy.com]  
-[防护服|http://019.google.591dy.com]  
-[商铺招租|http://018.google.591dy.com]  
-[户外广告|http://017.google.591dy.com]  
-[保温材料|http://016.google.591dy.com]  
-[防火材料|http://015.google.591dy.com]  
-[涂料|http://014.google.591dy.com]  
-[无痛流产|http://013.google.591dy.com]  
-[油漆|http://012.google.591dy.com]  
-[拓展训练|http://011.google.591dy.com]  
-[婚庆公司|http://010.google.591dy.com]  
-[旗袍|http://009.google.591dy.com]  
-[婚纱|http://008.google.591dy.com]  
-[管道疏通|http://007.google.591dy.com]  
-[婚纱摄影|http://006.google.591dy.com]  
+ Support for this feature is spotty . DanBernstein refuses to implement it and it doesn't seem to be mentioned at all in MicrosoftWindows (as of 2004-07-14) .  
+ Only [BIND ] seems to support it, but since it will also serve you a <tt>CNAME< /tt>, most resolvers should deal with it properly :  
+ <verbatim>  
+ test .meta .net .nz . 86400 IN DNAME wlug .org .nz .  
+ www .test .meta .net .nz . 0 IN CNAME www .wlug .org .nz .  
+ www .wlug .org .nz . 80464 IN CNAME hoiho .wlug .org .nz .  
+ hoiho .wlug .org .nz . 80464 IN A 203 .97 .10 .50  
+ < /verbatim>  
+ MicrosoftWindows still seems to get confused however . 
  
-[家政 |http ://005.google.591dy.com]  
-[家政服务 |http ://005 .google.591dy.com]  
-[家政服务公司 |http://005 .google .591dy .com]  
-[保姆 |http://005 .google .591dy .com]  
-[钟点工 |http: //005 .google .591dy .com]  
-[小时工 |http://005 .google.591dy.com]  
+__<tt>LOC</tt>__ :  
+ [GPS] location of the machine or site. Specified in RFC :1876 . Example:  
+ <verbatim>  
+ waikato .ac .nz . LOC 37 48 30 .000 S 175 17 36 .000 E 66 .00m 3000m 30m 10m  
+ < /verbatim>  
+ This means 37 deg 48' 30" South (latitude), 175 deg 17' 36" East (longitude), and 66 metres about sea level .  
+ The last two numbers appear to mean that the whole site is within 3000 metres of the given point .  
+ The point is accurate to about 30 metres, although this interpretation may be wrong .  
+ (It will be in the appropriate [RFC] if anyone can be bothered looking it up .)  
  
-[汽车坐垫 |http://004 .google .591dy.com]  
-[汽车坐垫代理 |http://004.google.591dy.com]  
-[汽车坐垫销售 |http://004.google.591dy.com]  
-[汽车坐垫生产 |http://004.google.591dy.com]  
-[北京汽车坐垫 |http://004.google.591dy.com]  
+ xtraceroute(1) will use these records if it can find them . Unfortunately not many sites use them . 
  
-[白癜风 |http ://003 .google .591dy.com]  
-[白癜风专家 |http: //003 .google.591dy.com]  
-[白癜风医院 |http ://003 .google.591dy .com]  
-[白癜风治疗 |http://003 .google .591dy .com]  
-[白癜风药品 |http: //003.google.591dy.com]  
-[白癜风信息 |http://003 .google .591dy.com]  
+__<tt>MX</tt>__ :  
+ MailExchanger . Identifies the [SMTP] MailServer(s) responsible for the domain .  
+ When no <tt>MX</tt> record exists and an <tt>A< /tt> record does, the <tt>A< /tt> record is chosen to take mail .  
+ Specified in RFC :1035 . Example:  
+ <verbatim>  
+ foo .com. IN MX 10 mail .foo .com.  
+ < /verbatim>  
+ The "10" is the priority . Delivery will be attempted to MailServer~s in order of ascending priority value . 
  
-[美容仪器 |http ://001 .google .591dy .com]  
-[美容设备 |http: //001.google.591dy.com]  
+ __Note :__ the data for an <tt>MX< /tt> record is a host name, __NOT__ an [IP] address . The following will __NOT__ work:  
+ <verbatim>  
+ foo .com . IN MX 10 130.123.7.10  
+ < /verbatim>  
  
-[空调清洗 |http://002 .google.591dy .com]  
-[中央空调清洗|http: //002.google.591dy.com]  
-[清洗空调 |http: //002 .google.591dy.com]  
-[清洗中央空调|http://002.google.591dy.com]  
+ Also, the host name (<tt>mail .foo .com< /tt> in the example) __MUST__ have an <tt>A< /tt> record, __NOT__ a <tt>CNAME< /tt> record . 
  
-[搬家公司 |http://google .591dy.com/banjgs/]  
-[造桥机 |http ://google .591dy.com/zqj/]  
-[中央空调 |http: //google.591dy.com/zhykt/]  
-[麦克维尔 |http ://google.591dy.com/mkwr/]  
-[管道疏通 |http://google .591dy .com/guandsht/]  
-[霓虹灯 |http ://google .591dy.com/nihd/]  
-[卫生洁具 |http://google.591dy.com/weishjj/]  
-[游乐设备 |http://google .591dy .com/youlshb/]  
-[游乐设备 |http: //google.591dy.com/youlshb/]  
-[乳胶漆 |http ://google.591dy.com/rujq/]  
-[塑钢门窗 |http://google .591dy .com /sugmch/]  
-[CI策划 |http://google .591dy.com/cich/]  
-[私人侦探 |http ://google .591dy.com/sirzht/]  
-[可视门铃 |http ://google.591dy.com/keshml/]  
-[律师事务所 |http://google.591dy.com/lvshshws/]  
-[驾校 |http://google.591dy.com/lvshshws/]  
-[轴承 |http://google .591dy .com/zhouch/]  
-[夜视仪 |http://google .591dy .com/yeshy/]  
-[高压清洗机 |http://google .591dy .com/gaoyqxj/]  
-[铁路标准 |http://google .591dy .com/tielbzh/]  
-[铁路工法 |http://google.591dy.com/tielgf/]  
-[架桥机 |http://google.591dy.com/jiaqj/]  
-[网站推广 |http: //www.starpioneer.com/]  
-[快餐 |http: //google .591dy.com/ ]  
-[订餐 |http: //google .591dy .com /]  
-[天花板 |http: //www .591dy.com/tianhb/]  
-[NEC交换机 |http ://www .591dy.com/necjhj/]  
-[印刷机械 |http ://google .591dy.com/yinshjx/]  
-[整形美容 |http ://google.591dy.com/zhengxmr/]  
-[糖尿病 |http://google .591dy.com/tangnb/]  
-[高血压 |http ://google.591dy.com/gaoxy/]  
-[建材 |http://google .591dy .com/jianc/]  
-[变压器 |http ://google.591dy.com/bianyq/]  
-[胶合板 |http://google .591dy .com/jiaohb/]  
-[热水器 |http://google .591dy.com/reshq/]  
-[楼市图 |http:/ /google .591dy.com/lousht/]  
-[二手车 |http: //google.591dy.com/ershch/]  
-[安防设备 |http ://google.591dy.com/anfshb/]  
-[继电器 |http://google .591dy.com/jidq/]  
-[传感器 |http ://google .591dy.com/chuangq/]  
-[对讲机 |http ://google.591dy.com/duijj/]  
-[宠物食品 | http://google .591dy .com /chongwshp /]  
-[猫粮 |http://google .591dy.com/maol/]  
-[狗粮 |http://google.591dy.com/goul/]  
+__<tt>NS</tt>__:  
+ Authoritative NameServer for a domain . Specified in RFC :1035 .  
+  
+__<tt>PTR< /tt>__ :  
+ A pointer . Used for a ReverseLookup . Specified in RFC :1035 . Example:  
+ <verbatim>  
+ 192 PTR hostname .domain .  
+ < /verbatim>  
+ __Note :__ don't forget the trailing fullstop!  
+  
+__<tt>SOA< /tt>__:  
+ Start of Authority . Defines information about a domain (called a zone, defined in a ZoneFile), such as a serial number defining the 'version' of the zone, and various timeout and caching values that should be used when records from a given zone are retrieved . The format <tt>name <ttl> class rr name-server email-address (serial refresh retry expire negttl)< /tt> . Specified in RFC :1035 . Example :  
+ <verbatim>  
+ $TTL 604800  
+ $ORIGIN ethernal .tla .  
+ @ IN SOA ns1 .ethernal .tla . root .ethernal .tla . (  
+ 2004111901 ; Serial  
+ 604800 ; Refresh (7 days)  
+ 86400 ; Retry (24 hours)  
+ 2419200 ; Expire (28 days)  
+ 604800 ) ; Neg TTL (7 days)  
+ < /verbatim>  
+ The name is given as "<tt>@< /tt>", since that is the shorthand for the value of <tt>$ORIGIN< /tt> . [TTL ] is missing from this example, as it takes the zone default defined above as <tt>$TTL< /tt> . The name-server field is basically the [FQDN] of the PrimaryNameServer for the domain (don't forget the trailing fullstop!) . The email-address field is the address of the person responsible for the domain -- the first dot should be read as an <tt>@< /tt>, so above should be read as <tt>root@ethernal.tla< /tt> . The values in parenthesis are described below:  
+  
+ Serial number ::  
+ Generally given in YYYYMMDDXX format, giving 100 possible revisions of any given zone in a day (Usually more than enough) .  
+ Refresh: :  
+ Defines the number of seconds before a SecondaryNameServer will refresh its copy of the zone by requesting a ZoneTransfer from the PrimaryNameServer .  
+ Retry: :  
+ Defines the number of seconds for a SecondaryNameServer to wait before retrying a zone refresh, after a failure .  
+ Expire: :  
+ Defines the number of seconds for a SecondaryNameServer to keep zone records, and answer authoritatively with them if it can't contact the PrimaryNameServer . (so, if the above refresh fails, and it's been retrying for this long) .  
+ Neg TTL: :  
+ Defines the number of seconds that a client should remember that a negative response was received from this server . So, if a remote server asks us what the address for <tt>foo .ethernal .tla< /tt> is but it doesn't exist, it will cache the negative answer we gave it for this many seconds, even if we add that name to the zone a couple of seconds later .  
+  
+__<tt>TXT< /tt>__ :  
+ Up to 255 bytes of arbitrary binary data . Specified in RFC :1035 .  
+  
+A more comprehensive list of ResourceRecord~s is at : http://www .dns .net /dnsrd /rr .html  
+  
+----  
+CategoryDns