Re: [cobalt-users] problems with Qube3 (was Macintosh, AppleShare IP Users)

["Rodolfo J. Paiz" <rpaiz@xxxxxxxxxxxxxx>]

At 4/5/01 02:10 PM -0500, you wrote:
> I am using the Qube 3 as a gateway with NAT - i.e., all my machines are on a
> 192.168.x.x network as is the secondary ethernet on the Qube 3. The Qube 3
> connects to the Internet through our DSL router using a real IP address on
> its primary ethernet. If I try an nslookup on my mail servers real IP
> address, I get the following
>
> DNS request timed out.
>          timeout was 2 seconds
> *** Cant' find server name for address 192.168.x.x: Timed Out
> Server:  sextant.bluestar.net
> Address:  209.119.96.2
>
> *** sextant.bluestar.net can't find 64.183.17.34: Server failed
>
> The actual address it gives for the internal IP is correct for my mail
> server's internal IP. sextant.bluestar.net is our Primary DNS server at the
> ISP. I am not running DNS at all myself.

And we have a winner! You have found your problem, and it is as I described 
in the previous message: there is no reverse DNS at all, and so sendmail's 
query is timing out and making you wait. But there is a simple fix:

There is a file called /etc/host.conf; if you read it, it says something like

order hosts,bind

That means your server will first check the contents of the /etc/hosts file 
for name<->number conversions, and if no answer is found then it'll ask 
bind (the DNS server). So, you need to ensure that the IP's on your 
internal network have entries in either bind or /etc/hosts.

Since /etc/hosts is simpler and gets checked first anyway, you should add 
them here. Simply add lines like the following to /etc/hosts:

209.119.96.2    <tab>   sextant.bluestar.net    <tab>   sextant

The first is an IP address, the second is the full name (including domain) 
of the machine, and the third is a nickname (usually just the hostname). Do 
this for all IP's...

192.168.0.1             ip-0-1.internal.net             ip-0-1
192.168.0.2             ip-0-2.internal.net             ip-0-2
192.168.0.3             ip-0-3.internal.net             ip-0-3
192.168.0.4             ip-0-4.internal.net             ip-0-4
192.168.0.5             ip-0-5.internal.net             ip-0-5
192.168.0.6             ip-0-6.internal.net             ip-0-6

ad infinitum. If you are using this address space as a Class B, I 
*strongly* suggest you do this in Excel, where you can autonumber and 
create the 65,536 lines you need in about 30 seconds, then export to 
notepad, then upload to server, cut/paste into /etc/hosts. Otherwise, 
well... you're going to be here for a while.

I'd give 10:1 odds that your mail goes through blindingly fast from now on. 
Until something else goes wrong, that is; something always does.

Touching on a comment made recently (not sure whether by you or someone 
else), which said "I sure hope Cobalt issues fixes for this and other 
issues soon," I'd like to suggest that, although Cobalt does need to 
improve, it is usually (a) beneficial and/or (b) educational to investigate 
the crap out of anything you find. You'll either fix it yourself or learn a 
lot while doing it. And some things *aren't* their fault.

Hope this helps...


--
Rodolfo J. Paiz
rpaiz@xxxxxxxxxxxxxx