Stephen Gran on 21 Mar 2006 16:34:41 -0000


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Re: [PLUG] DNS question


On Tue, Mar 21, 2006 at 11:19:37AM -0500, George Gallen said:
> but if it's in the /etc/hosts file, it SHOULD have a reverse entry.
> 
> If it's the ftp server doing the reverse lookup, I would think the
> pause would occur whether I'm using IP direct or a DNS (the server
> side shouldn't have any way to know if I used DNS to get it's address).
> 
> I'm ftping out to another machine, For now I can use direct IP, but
> it's easier to use a label in case the IP changes I only have to change
> it in one place (/etc/hosts).

Can you strace the two processes?  That is really the only thing that
will tell the difference between what's going on.

If you are familiar with strace and it's output, you should be able to
tell relatively quickly what the delay is - extra lookups, whatever.

If you are unfamiliar with strace, what I am looking for is the output of 

strace -o by_ip -ff ftp 1.2.3.4
strace -o by_name -ff ftp hostname

You will get a couple of files output (and your ftp session will be
really slow :).  Can you then put them online, and I'll try to take a
look at them?  If they are small, feel free to send them off list, but
strace output is usually huge.

Be aware that strace _will_ contain private data - IP addresses, ftp
passwords, paths to files, etc.  If you feel uncomfortable sharing this
information, I quite understand.  I just don't have any other suggestions
for helping you at the moment.  You can of course edit the files before
sharing them, or put them in a password protected directory on an https
server, and then decide you trust me ;)

Take care,
-- 
 --------------------------------------------------------------------------
|  Stephen Gran                  | There is no TRUTH.  There is no         |
|  steve@lobefin.net             | REALITY.  There is no CONSISTENCY.      |
|  http://www.lobefin.net/~steve | There are no ABSOLUTE STATEMENTS.   I'm |
|                                | very probably wrong.                    |
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