Difference between revisions of "OPS535 Notes"
| Line 53: | Line 53: | ||
What if it is coming from the name server for senecac.on.ca? | What if it is coming from the name server for senecac.on.ca? | ||
| − | * (a) Let take look or talk to the DNS administrator of senecac.on.ca domain | + | * (a) Let's take a look or talk to the DNS administrator of senecac.on.ca domain |
* (b) it depends on what kinds of DNS records | * (b) it depends on what kinds of DNS records | ||
Revision as of 11:07, 26 November 2014
Absolute and relative paths
- File system example:
learn name: rchan account on matrix: /home/rchan file system: the root (the starting point - from the right) is /
Host name and Fully Qualify Domain name (FQDN)
- DNS system:
host name: www FQDN for the host: www.senecac.on.ca. (note the '.' at the end) dns system: the root (the starting point - from the right ) is . (dot)
what is the minimum of partition(s) do you need to install Linux?
(a) 1 - 1 (v) - root file system (b) 4 - 4 (c) 2 - 2 (d) 3 - 4
. domain - root domain - root name server
note: All caching only DNS servers must know who are the root name servers (i.e. their IP addresses)
Look up the IP for "scs.senecac.on.ca"
Caching name server will ask one of the 13 root name server the question: what is the IP address for scs.senecac.on.ca
Answer back from the root name server:
Sorry! I don't know, but you can ask the name server for the "ca" domain,
And here is its name (xxxxx) and ip address (ddddd)
....
Caching name server will ask one of the Name server for the senecac.on.ca domainthe question: what is the ip address for scs.senecac.on.ca
possible answers:
(1) There is no such host. (2) the ip for that host is 142.240.140.179
What will be the TTL for the cached records in the caching name server.
- (a) 7 days
- (b) forever
- (c) 15 minutes
- (d) depends on where is coming from (v)
What if it is coming from the name server for senecac.on.ca?
- (a) Let's take a look or talk to the DNS administrator of senecac.on.ca domain
- (b) it depends on what kinds of DNS records
Is there a field in each DNS record that we can specify the TTL?
Answer: Yes. there is a global TTL field and a local TTL field for each record in the zone file
Why do we need such kind of information?
Answer: So that the authoritative DNS server for the DNS record is still in control of the DNS mappings.
Does your primary name server need the information about the 13 root name servers?
Yes/no and why?
No, no, no. if you don't want your primary name server to keep any DNS cache!
