Time |
2007-10-03 7:00pm (90 mins) |
Location |
Chamberlin Hall, 1150 University Ave 4th Floor |
recording |
Purpose of DNS (problem definition)
- names for humans, numbers for computers - ancient history, the /etc/hosts file
- distributed control (ownership)
- distributed service (redundancy, availability)
DNS Client behaviour
- lookup mechanisms and behaviour
- overriding DNS with local names (use /etc/hosts)
Total system picture
- authoritative servers
- resolvers (caching, forwarding)
- domain registration and DNS
Record types
- A and AAAA, IPv4 and IPv6 addresses for known names
- PTR records, getting the name(s) for a given IP
- MX, mail eXchangers (where to send mail messages)
- NS and SOA, plumbing records
- TXT and SRV, rare records
- CNAME records (aliases)
Command line tools
- nslookup (one of the oldest)
- host (common, simple)
- dnsq (and the other djbdns-tools)
Servers
- BIND (a very common DNS server)
- djbdns (tinydns and dnscache)
- maradns
- pdns
Odds and ends
- DNS sequence numbers
- packet signatures (UDP and TCP)
A picture of the DNS system:
