lsg30.htm

linux-unix130.linux.and.unix.ebooks130 linux and unix ebookslinuxLearning Linux - Collection of 12 E

<FONT SIZE=4 COLOR="#FF0000"><B>Resource Records</B></FONT></CENTER></H4>



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<P>The name server maintains the information required to resolve symbolic names to their IP addresses in a set of resource records, which are entries in a database. Resource records (often abbreviated to RR) contain information in ASCII format. Because ASCII is used, it is easy to update the records. Each RR has a specific format:



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<FONT COLOR="#000080">domain_name, type, class, TTL, Routing_Data</FONT></PRE>



<P>The domain name field is the machine the record refers to. If no name is specified, the name in the previous RR is used. The Type field identifies the type of resource record. The different types of resource records have different purposes, such as mapping names to addresses and defining zones. A mnemonic code or a number identifies the type of resource record. These codes and their meanings are listed in Table 30.1.



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<FONT COLOR="#000080"><B>Table 30.1. Codes and numbers for resource record types.</B></FONT></CENTER>



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<TABLE  BORDERCOLOR=#000040 BORDER=1 CELLSPACING=2 WIDTH="100%" CELLPADDING=2 >



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



<I>Number</I>



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



<I>Code</I>



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



<I>Description</I></FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



1



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



A



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Network address</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



2



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



NS



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Authoritative name server</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



3



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MD



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mail destination. Now replaced by MX.</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



4



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MF



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mail forwarder. Now replaced by MX.</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



5



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



CNAME



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Canonical alias name</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



6



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



SOA



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Start of zone authority</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



7



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MB



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mailbox domain name</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



8



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MG



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mailbox member</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



9



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MR



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mail rename domain</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



10



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



NULL



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Null resource record</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



11



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



WKS



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Well-known service</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



12



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



PTR



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Pointer to a domain name</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



13



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



HINFO



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Host information</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



14



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MINFO



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mailbox information</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



15



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



MX



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Mail exchange</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



16



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



TXT



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Text strings</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



17



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



RP



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



Responsible person</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



18



</FONT>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



AFSDB



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<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



AFS-type services</FONT>



<TR>



<TD VALIGN=top  BGCOLOR=#80FFFF ><FONT COLOR=#000080>



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