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New to Linux Part Deux

PostPosted: Sun Jul 27, 2003 8:35 pm
by Webdiggity
Ok, I have a little problems here. My server is up and running just fine. I purchased/leased a dedicated box on Friday. Nothting wrong with the server yet. All of my customers are pointing their domains at the name servers for my provider. (They have a nice tool)

When I use their tool to make dns entries for my customers and put in the ip. It's reflected immediately. They resolve at the dedicated server. My domain, however will not resolve. The hostname for the server is dig2.mydomain.com and the domain I use is www.mydomain.com. YOu get the picture.

I used their dns tool to point my domain at the server. It's been 8 hours since I made the change and it's still resolving to the old server. This is making me nuts!

Any ideas why all the other will resolve instantly but mine will not?

Thanks in advance,
Webdiggity

P.S. I'm not trying to spam a forum with my domain name as it is a business but if you need it for troubleshooting purposes I will provide it.

PostPosted: Sun Jul 27, 2003 8:46 pm
by Void Main
What is the TTL set to on your domain DNS records? Remember that records will stay in cache until the TTL expires. New records will show up immediately because they are not yet cached. Cached records stay in cache until TTL expires before going back to the DNS server responsible for that domain for a new query which would place the new record in cache. The cache I am referring to is the DNS server(s) that your local machine (the one you are typing on) is pointed to.

PostPosted: Sun Jul 27, 2003 9:15 pm
by Webdiggity
I'm using my provider's name servers. So I have no idea how long it will take. The one's I haven't been fooling with resolve immediately. Two of them that have been on there are not resolving very quickly. The ones I just changed are already resolving the ones I've been playing with this weekend are not resolved yet. Nearly 8 hours. :)

P.S. What is TTL? Sorry, noobie here.

I also started putting linux on a machine. Is Slackware any good? I heard I can get it down to a smaller footprint. I was going through the installation and didn't know what packages needed to be installed or not. What is mandatory and what is not. Do I need to use a swap partition? All that good stuff.

Void, this is a killer website. Check ya later!

PostPosted: Mon Jul 28, 2003 9:00 pm
by Void Main
TTL = Time to Live. It's how long a record stays in cache. For instance, when you come to my site you typed http://voidmain.is-a-geek.net/ into your browser. As you know in order to actually make a connection to my site your system has to be able to resolve my host name into an IP address. Assuming you are on a Windows machine you can do an "ipconfig /all" to see what DNS servers your PC is pointing to. Your machine asks the first DNS server in the list for an IP address for voidmain.is-a-geek.net. Chances are, the servers your client is pointing to is not authoritative for the is-a-geek.net domain so it has to ask the root servers responsible for the .net TLD (top level domain) for the authoritative server for is-a-geek.net. Once the root server gives your local DNS server that information it goes and queries the authoritative server for voidmain.is-a-geek.net and saves the record in it's own cache for the period of time specified in the TTL part of the record. That way it doesn't have to keep going out and asking the authoritative server as often. Usually static IP addresses will have a high TTL, at least day and very possibly more than that.

So if you do a "dig voidmain.is-a-geek.net" you will get something like this:

Code: Select all
; <<>> DiG 9.2.1 <<>> voidmain.is-a-geek.net
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61508
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 5, ADDITIONAL: 2
 
;; QUESTION SECTION:
;voidmain.is-a-geek.net.                IN      A
 
;; ANSWER SECTION:
voidmain.is-a-geek.net. 60      IN      A       24.171.59.228
 
;; AUTHORITY SECTION:
is-a-geek.net.          86400   IN      NS      ns1.dyndns.org.
is-a-geek.net.          86400   IN      NS      ns2.dyndns.org.
is-a-geek.net.          86400   IN      NS      ns3.dyndns.org.
is-a-geek.net.          86400   IN      NS      ns4.dyndns.org.
is-a-geek.net.          86400   IN      NS      ns5.dyndns.org.
 
;; ADDITIONAL SECTION:
ns1.dyndns.org.         85850   IN      A       66.151.188.43
ns3.dyndns.org.         85850   IN      A       64.152.102.41
 
;; Query time: 57 msec
;; SERVER: 192.168.0.3#53(192.168.0.3)
;; WHEN: Mon Jul 28 21:46:36 2003
;; MSG SIZE  rcvd: 188


I run my own DNS server in my house (192.168.0.3) so that is what my DNS server thinks my IP address is. This is actually a bad example because I have a dynamic IP address and you can see the TTL for my record is only 60 seconds. That means that voidmain.is-a-geek.net should only reside an a DNS cache for 60 seconds before it is dropped and has to be requeried from the authoritative server, in this case ns1.dyndns.org through ns5.dyndns.org.

Say my TTL was set to what the default is on the zone (86400 seconds, or 1 day), to see what my local DNS server thinks voidmain.is-a-geek.net is I would type "dig voidmain.is-a-geek.net" just like in the first example. If I wanted to see what the authoritative server actually has for voidmain.is-a-geek.net I would type "dig voidmain.is-a-geek.net @ns1.dyndns.org". If I wanted to check the MX record I would type "dig MX voidmain.is-a-geek.net". Of course Windows doesn't come with the "dig" command like most every other operating system so if you want to run it on Windows I believe there is a Windows version of it out there somewhere. Of course there are many other ways to trace DNS. I used to use the "nslookup" command but "dig" is a little easier.

If you are going to be hosting sites it would benefit you to learn how to trouble-shoot DNS issues. I prefer to run my own servers so if something is broken it's going to be my own fault. The good part is, I have the power to correct the problem and don't have to wait on anyone else.

PostPosted: Mon Jul 28, 2003 9:07 pm
by Webdiggity
Needless to say, I'm learning volumes each day. Thanks to my problems. I got the server straightend out tho and your explanations are very informative.

Thanks a bunch!

Webdiggity