LPI Linux Certification/Create & Maintain DNS Zones
Detailed Objectives
edit(LPIC-2 Version 4.5)
Weight: 3
Description: Candidates should be able to create a zone file for a forward or reverse zone or root level server. This objective includes setting appropriate values for records, adding hosts in zones and adding zones to the DNS. A candidate should also be able to delegate zones to another DNS server.
Key Knowledge Areas:
- BIND 9.x configuration files, terms and utilities.
- Utilities to request information from the DNS server.
- Layout, content and file location of the BIND zone files.
- Various methods to add a new host in the zone files, including reverse zones.
Terms and Utilities:
/var/named/
- zone file syntax
- resource record formats
- named-checkzone
- named-compilezone
dig
nslookup
host
Create and maintain DNS zones
editDNS zone files are composed mostly by resources records (RR) Resource records must start in the first column of a line The order in which they appear is not important, but most people tend to follow the order in the DNS RFCs SOA (Start Of Authority) : indicates authority for this zone NS (NameServer) : lists a nameserver for this zone Other records :
A : name-to-address mapping PTR : address-to-name mapping CNAME (canonical name) : aliases Don't forget to create a zone for 127.0.0 ! Create and maintain DNS zones Usual zone file format :
$TTL <ttl value> <domain name>. IN SOA <nameserver name>. <user.email>. ( <serial>; serial number <refresh>; refresh value <retry>; retry value <expire>; expire value <n-ttl>; negative caching TTL of 1 day <domain name>. IN NS <authoritative NS name>. <domain name>. IN NS <authoritative NS name>. ... <hostname>. IN A <IP address> <hostname>. IN A <IP address> ...
Create and maintain DNS zones For reverse mappings : $TTL <ttl value> <reverse net addr>.in-addr.arpa. IN SOA <NS name>. <user.email>. ( <serial>; serial number <refresh>; refresh value <retry>; retry value <expire>; expire value <n-ttl>; negative caching TTL of 1 day <rev net addr>.in-addr.arpa. IN NS <authoritative NS name>. <rev net addr>.in-addr.arpa. IN NS <authoritative NS name>. ... <rev IP addr>.in-addr.arpa. IN PTR <fqdn>. <rev IP addr>.in-addr.arpa. IN PTR <fqdn>. ...
Key terms, files and utilities : Content of /var/named Zone file syntax Resources record formats Dig Nslookup Host
Exercises
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