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about TTL, DNS, TTL on a workstationNT, and perhaps UNIX DNS

A

abc

Diamond Member
this is sort of a real world situation, I hope I can explain the scenario, and possibly gain some interest and thoughts.Thanks in advance.

say there is Domain1 in NY, branch office, and Domain2 in Canada, headquarters.

Say DNS is administered in Canada, UNIX based DNS (FYIperhaps you can consider the flavor of DNS Server irrelevant as you read...)
and NY physically has 1 UNIX 'member?' server to which it periodically receives a copy of the database (replication kinda thing like MS pdc/bdc)

Say a NT workstation in NY, in Domain1... open a DOS box and PING a hostname within Domain1, no problem.

Say this same workstation or any within Domain1 PING a hostname OUTSIDE of domain1... that is, a hostname of a server in Canada, in Domain2.

The problem is when you PING the hostname: server.canada.com, you do NOT get an IP address, it fails.


2 seconds later, you PING the same hostname, and you DO GET THE IP ADDRESS, but out of the 4 ping replies, the 1st reply you wait the longest to recieve... about 6 seconds. the 2nd thru 4th replies come 1 second after another.

If you DO NOT ping the hostname again for about 15minutes... it will fail again... unless you again PING it 2 seconds later.

IF YOU PING THE IP, NOT the hostname, it will always reply, no delay, no need to ping 2x.


Somebody has suggested this to me. The UNIX DNS server in Domain1, in NYC, only stores Host IP information for machines within "Domain1", requests for IPs outside of Domain1 (such as this case) will be forwarded to a upstream server.

The results of the query will be then received and kept in our DNS CACHE in Domain1, with a LIFETIME defined in TTL from the DNS Servers in Domain2... ( as stated, where DNS is administered for the whole company, globally and Domain1 has no means to modify the TTL)

This was also mentioned to me:
Also, the period of forwarding requests ( i guess he means the frequency or interval of forwarding the query results for IPs?) from other DNS servers is longer than the TIMEOUT limit from ther user's station (NT workstations in Domain1)... that is why users had PING fail at first try, until this record is available in our DNS cache.

Hmm... can I modify anything in WinNT workstation to increase this TIMEOUT LIMIT?

Alternatively I can ask the people in DOMAIN2 to change some setting in their DNS?

Any workaround on the nt workstation I can apply?

how about putting the hostname and ip into the host file?
 
-Are these all NT domains that you are referring to?

-Who is the "he" that you mention - "...i guess he means the frequency or interval of forwarding the query results..."

-What DNS server pri & sec do you have setup for this WinNT workstation?

-What exactly is *broken* on this WinNT workstation? Or how is it limiting you in your day-to-day tasks?

-Are there any NT servers performing DNS for this network? Or are they all Unix servers?
 
yes, all (both) are NT domains. all Users of ea. domain authenticate via a third domain... call it DomainGlobal.

The 'HE' is the person who mentioned about the DNS cache in Domain1, etc.... basically somebody else trying to help me understand this issue to some extent.

What DNS server do the workstations in DOMAIN1 (NY) set up to? Set up to a UNIX based DNS system
where the parent UNIX DNS server is in Domain2 in Canada.

What is Broken? Good question. It is a Application on the workstation. The application is a Interface to a database, requires
a login via username and password. After they are entered, the application wants to connect to the database server.

The database server resides within Domain2, in Canada.

To connect to the server the application needs to talk to it. To talk to it it needs to resolve its Hostname.. .server.canada.com to IP address.

The server has Sybase.

The workstations containing the application rides on top of Sybase Client 11.

There are no NT servers doing DNS, pure UNIX.


Today I tried to mess with the host file within the workstation.

Ultimately what I wanted to do was put the IP of the Sybase Server (server.canada.com) and its IP address 10.x.x.x

I was hoping therefore the application would then NOT need to request any DNS resolving, as now that hostname is in the host file,
and so when you launch the application, it looks a the host file.... just as IE would look at a hostfile when you enter for ex. yahoo.com


To test, did nslookup on www.google.com, got the IP

open the host file, pasted google's IP, BUT I put in a host name of anandtech.com


I was thinking that when I open IE and type in anandtech.com, IE would look at the host file, find the IP of anandtech AS GOOGLE'S

and then bring up google.com for me.... it did NOT. brought up a error page. WHY???

This has worked at my home on my home pc.


 
did i have to reboot the pc for the host file to work in resolving anandtech to googlesIP?
 
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