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Date:      Thu, 08 Apr 1999 10:30:37 -0400
From:      Phil Wang <Phil.Wang@wizeup.com>
To:        Alan Weber <aaweber@austin.rr.com>, andyo@prime.net.ua
Cc:        questions@freebsd.org
Subject:   Re: FreeBSD server too slow for internals
Message-ID:  <370CBD8D.B24D834C@wizeup.com>
References:  <353CD4ED.37E7FCFA@wizeup.com> <370933AB.28F5D255@wizeup.com> <19990406133756.A728@austin.rr.com>

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Thank you all.

I do not solve the problem yet, and would like to offer the further
info.

1. My FreeBSD machine is a gateway which bridges Internet and an
internal network.

           209.83.165.224 ------------  192.168.1.1
Internet <---------------0  Gateway  0-------------> internal
                          ------------

2. It is not a DNS problem since the elapsed time is similar to ping
192.168.1.1 and 209.83.165.224 on the gateway or an internal machine.

3. It is not a firewall problem becasue NATD did not work only in that
period. NATD works well now and any internal machines access Internet
without an obvoius delay.

4. I have tested local TELNET and FTP on the gateway, and the result is
that telnet and ftp to 209.83.165.224 take less than 1 second and but
that telnet and ftp to 192.168.1.1 take 3 minutes. They are local
connections!

If somebody attacked this gateway, what had he done?

Looking forward to your reply.
Phil

> 
> On Mon, Apr 05, 1999 at 06:05:31PM -0400, Phil Wang wrote:
> --> Hi all,
> 
> --> I got a strange problem with my FreeBSD 2.2.5 machine, which is used as
> --> mail/pop3, ftp and httpd servers. Two network interface cards are
> --> installed on it, one is used to connect Internet, another is to connect
> --> an internal network. All machines (PC and MACs) internal network use
> --> NATD to do external access.
> 
> --> This morning, we found at first that a pop3 client took more than 5
> --> minutes to download emails from this pop3 server (sometimes failed), and
> --> later found that ftp and httpd services did too. It was very quick last
> --> Thursday, this machine was not turned down during the following
> --> holidays.
> 
> --> But it looks no slow to access those servers from external Internet or
> --> access Internet from internal machines. So, what is the problem?
> 
> --> I checked all the logs outputed from system processes, only one message
> --> repeated several times in /var/log/message may be useful.
> 
> --> <First appeared>
> --> Apr  2 11:08:19 wizeup natd: failed to write packet back (Permission
> --> denied)
> --> Apr  2 11:08:49 wizeup natd: failed to write packet back (Permission
> --> denied)
> --> Apr  2 11:10:54 wizeup last message repeated 4 times
> --> Apr  2 11:13:10 wizeup last message repeated 4 times
> --> Apr  2 11:13:21 wizeup popper[11123]: (v2.4b2) Unable to get canonical
> --> name of c
> --> lient, err = 0
> 
> This looks like the server can not find itself in the DNS system. If your
> local DNS is not working, then all of the connections could take a long
> time. Unable to get cannonical name of client indicates to me that the
> reverse dns ip number to name lookup is not working.
> 
> --> Does any body help it?
> 
> --> Thanks,
> --> Phil
>


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