DNS Workshop

1. DNS Workshop Mark Elkins A founding member and Technical Director of UniForum SA, Author of the COZA DNS System, Owner of Posix Systems - a 'Large', 2nd tier ISP, ..and has been around playing with the Internet before it was commercially available in South Africa. mje@posix.co.za

2. Why DNS • An IP Address has 2^32 or over 4 billion permutations • Names are easier to remember • HOSTS files are not scalable • Traffic load • Name collisions • Consistancy • One Machine with one IP address can have many different names (Virtual Web Server)

3. DNS is Scalable • It Works (usually) • Can be fault tolerant • DNS allows for downward delegation of responsibility

4. Using BIND • Berkeley Internet Name Domain software - Versions • Example Lookup www.posix.co.za • Nameserver Types • None • Cache Only • Secondary • Primary '.' + 'za' + 'co' + 'posix' + 'www'

5. Setting up your own Zone Comments ; /etc/ns.d/db.pearce.co.za ; Last Update: mje99!mje ttyp2 : 21 Aug 02 15:07 ; ; Don't forget to change the serial Number whenever any of the files ; are changed! The format is YYYYMMDD?? Timeouts and authorities $TTL 864000 @ IN SOA mje99.posix.co.za. dns-admin.posix.co.za. ( 2002082100 ; Serial number 864000 ; Refresh after 10 days (secs) 36000 ; Retry after 10 hours 3600000 ; Expire after 42 days 864000 ) ; Minimum TTL 10 days

6. Setting up your own Zone Nameservers IN NS mje99.posix.co.za. IN NS secdns1.posix.co.za. Mail Exchangers IN MX 0 mercury.pop.co.za. IN MX 10 secdns1.posix.co.za. IP for the Zone IN A 160.124.208.1 Other Information localhost IN A 127.0.0.1 ftp IN A 160.124.208.1 webftp IN A 160.124.208.1 www IN A 160.124.208.1

7. Named.conf entries Primary entry zone "pearce.co.za" { type master; file "db.pearce.co.za"; }; Secondary entry // Added 2002-06-06 18:17:18 (Thu) zone "pearce.co.za" { type slave; file "posix/sec/db.pearce.co.za"; masters { 160.124.48.1; }; };

8. Setting up a Reverse Zone ; /etc/ns.d/db.160.124.49 ; Last Update: mje99.posix.co.za!mje ttyp9 : 29 Apr 98 16:50 ; ; Don't forget to change the serial Number whenever any of the files ; are changed! The format is YYYYMMDD?? $TTL 864000 @ IN SOA mje99.posix.co.za. dns-admin.posix.co.za. ( 2001022809 ; Serial number 864000 ; Refresh after 10 days (secs) 36000 ; Retry after 100 mins 3600000 ; Expire after 42 days 864000 ) ; Minimum TTL 10 days IN NS mje99.posix.co.za. IN NS secdns1.posix.co.za. 0 IN PTR posix.co.za. 10 IN PTR headmaster.entrepreneurship.co.za. 11 IN PTR tux.ukusiza.co.za. 12 IN PTR ecom.e-way.co.za.

9. Named.conf Reverse entries Primary zone "49.124.160.in-addr.arpa" { type master; file "db.160.124.49"; }; Secondary zone "49.124.160.in-addr.arpa" { type slave; file "posix/sec/db.160.124.49"; masters { 160.124.48.1; }; };

10. CO.ZA Form (Part 1) Form Header UNIFORUM S.A. COZA Registration Office Last Change - 02 September 1998 Domain 1a. Complete domain name:pearce.co.za 1b. Action - [N]ew, [U]pdate, or [D]elete (N/U/D) : N Registrant and Billing 2a. Domain Owner: Gary Pearce 2b. Owner Postal address: P.O. Box 77305 Eldoglen 0171 2c. Owner Street address:8 Shilling Close, Eldoglen, Centurion 2d. Cost of this application (150 + 50/0):200 2e. On [A]ccount, [I]nvoice me or [C]heque on its way (A/I/C):I 2f. Organisation to be billed or account no. : Gary Pearce 2g. E-Mail address to send invoice to:gary@paceoil.co.za 2i. Inv. Addr:P.O.Box 77305 Eldoglen 0171 2j. Owner Phone No.: 082 440 9635 2k. Owner Fax No. :012 658 0294 2l. Owner e-mail :gary@paceoil.co.za

11. CO.ZA Form (Part 2) Admin Contact 4a. Name (last, first):Pearce, Gary 4b. Title/position: Owner 4c. Organisation:Private 4d. Postal Address: P.O.Box 77305 Eldoglen 0171 4e. Phone Number: 082 440 9635 4f. Fax Number:012 658 0294 4g. Email address:gary@paceoil.co.za 4h. NIC assigned Handle (if known): Technical Contact 5a. Name (last, first):Elkins, Mark 5b. Title/position:Director 5c. Organisation: Posix Systems (Pty) Ltd 5d. Postal Address:P.O. Box 73892, Lynnwood Ridge, 0040 5e. Phone Number: 012 807 0590 5f. Fax Number:012 807 5324 5g. Email address:dns-admin@posix.co.za 5h. NIC assigned Handle (if known): MJE Nameservers 6a. Primary server FQDN:mje99.posix.co.za 6b. Primary server IP address:160.124.48.1 6e. Secondary server FQDN: secdns1.posix.co.za 6f. Secondary server IP address:160.124.112.10

12. CO.ZA technical limitations • One application per e-mail • Application must be ASCII • No Word/DOC, UU/Base-64/HTML Encoding • Don't do ORG.ZA domains - only CO.ZA • Need a Domain Name, only a Domain Name. • Up to 30 Chars • No Naked Hyphens • No double Hyphens (Multi-language) • All needed fields are supplied • E-mail fields must look like valid e-mail addresses • Phone Numbers must look like phone numbers • IP Addresses must be valid • Nameservers must be valid • Nameserver must have a reverse • Nameservers must be reachable • Cross check between Zone and Nameservers must work

13. Potential Changes to COZA • Removal of MX entries • Glue - a Sticky problem • Pre-Registration of NameServers - the .COM way • Pro's & Cons • Registration of Nameservers in a Domain • Pro's & Cons • Restriction to the CO.ZA Zone • Only use 'registered' nameservers

14. Odds & Ends • Recursive search for Glue rat.co.za --> ns.v-e-s.com & ns1.v-e-s.com ==> No A Records v-e-s.com --> ns1.rat.co.za & ns2.rat.co.za ==> No A Records (recently changed to ...is.co.za) • Nameserverless domains globe --> ns.dragon-dbn.co.za. & ns2.dragon-dbn.co.za. ....but there is no 'dragon-dbn.co.za'

15. Summary • Why DNS? • DNS is scalable • Using BIND • Setting up your own Zone • named.conf entries • Setting up a Reverse Zone • CO.ZA application • CO.ZA technical limitations • Changes to how CO.ZA works • Odds and Ends