Re: ping taking a LONG time

[rob@xxxxxxxxx]

Thank you Scott for that explanation.

I don't know why it's running faster now though.

Rob Berendt
-- 
"They that can give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." 
Benjamin Franklin 




Scott Klement <klemscot@xxxxxxxxxxxx> 
Sent by: midrange-l-bounces@xxxxxxxxxxxx
09/26/2003 03:02 PM
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Subject
Re: ping taking a LONG time







It sounds like it's waiting for the reverse DNS lookup to time-out.  For
whatever reason, the iSeries PING will first do a "forward DNS lookup" to
get the IP address of the host you want to send the ping to, and then it
does a reverse lookup on that address to get back the name.

For example, let's say I have an iSeries called "bigbertha.example.com"
and I have "iSeries.example.com" set up as an alias for that.

If I type:

ping iseries.example.com

it sends back a messae like this:

Verifying connection to host system BIGBERTHA.EXAMPLE.COM at address
  192.168.0.1.

How did it know that "iseries.example.com" was also called "bigbertha"?
Because it first got the address, then did a reverse-lookup on that
address to get the "canonical" hostname.

Okay, now that I've explained all of that...   your problem sounds like
the reverse DNS is waiting to time-out.

On FreeBSD I can specify an option to tell it not to do DNS (which is
useful in networks that don't have a DNS server) but the iSeries doesn't
appear to have this feature.


On Fri, 26 Sep 2003 rob@xxxxxxxxx wrote:

> In my dmz if I do a
> ping myother400
> it takes forever for it to return any information, like a minute or so.
> Once it does it claims that all tries were sub millisecond.
> But if I do a ping xxx.xxx.xxx.xxx in which xxx... is the ip address of
> the other 400 it works as usual.
>
> I checked CFGTCP-12-Change TCP/IP domain information to see if it search
> local hosts table first or the 3 external DNS' set up.  It does use
> Host name search priority  . . .   *LOCAL
> and there is a host table entry for myother400.
>
> Any idea's where the hold up might be?
>
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