[plug] DNS resolution in detail

Matt Kemner zombie at networx.net.au
Mon Nov 16 09:33:14 WST 1998


On Sat, 14 Nov 1998, Leon Brooks wrote:

> The first time I did this, I learned a lot of picky details about my own
> DNS setup (for example, the automatic checker doesn't like using CNAME
> records for anything important),

That's because the RFCs say you shouldn't use CNAMES for anything
important.
For example, everytime I send mail to you, my named complains because the
MX
record for brooks.smileys.net points to a CNAME - you need to point it to
an existing record instead. Just change the line  
brooks		IN	MX	20 server
  to:
brooks		IN	MX	20 happy

And all the world's name servers (that have to deal with yours) will be
happy.

> No, the ISP can set up his own DNS more or less instantly, but the
> outside world won't know the details until the appropriate root DNS
> tells them to look there.

auNIC's email that tells you they've added you to the database,
says to wait 24 hours before the change will be visible to the world.
Also, depending on the status of the ISP with MelbIT, a .com.au domain can
take up to 5 days to get delegated, after the request was made - so
during that time your domain will be visible at the ISP but not to the
world.  It seems that the more domains an ISP registers through MelbIT,
the faster the registration process happens.

> It's even possible to set up a DNS that doesn't resolve to real
> addresses. For example, there is a DNS set up to play adventure! You
> start dnslookup, tell it to use that DNS as a server, query all types of
> DNS record, and that your domain is "adventure."
> 
> I don't have the address any more, but know who to ask if you're
> interested.

nslookup - hastur.rlyeh.net
Default Server:  hastur.rlyeh.net
Address:  193.215.252.2

> set querytype=txt
> set domain=adventure
> 1
Server: hastur.rlyeh.net
Address: 193.215.252.2
1.adventure	text = "You are walking along a country road, you     \
                        spot a pizza lying in the middle of the road. \
                        You are ravenous with hunger. Do you (2) walk \
                        past, or (3) attack the poor helpless pizza?"

Unfortunately hastur seems to be down at the moment.  It's a lot of fun
though :)

The UCC talked about this name server last month, and someone suggested
settup up a file server through DNS - just send uuencoded files through
the text records.  That's one way to bypass corperate firewalls. :)

 - Matt



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