Slow telnet, POP3, SMTP through ISDN router using DIAT

Slow telnet, POP3, SMTP through ISDN router using DIAT

Post by Mike » Wed, 22 Jul 1998 04:00:00

I have some users opn a Linux Internet server, getting in via Shiva
Accessport ISDN routers and a Shiva Lanrover Dialup rack.

When a user on the outside of a Shiva Accessport using DIAT tries to get
mail or send mail there is a 10 second delay before making a connection.

I am running Redhat Hurricane with DNS running OK and reverse entries
for the server and isdn dialup ports.

This does not happen with modems and the same user etc.

So I think its because the ISDN router is hiding the IP address or its

Or maybe the Linux box needs to make a return connection before it can
complete an SMTP transaction, and the return path is not defined in the
DIAT table.

I could disable DIAT at the user end but this opens his security I

Anyone got any ideas?

(I assume that /etc/hosts does not matter as I am using DNS).


1. iptables firewall making smtp/pop3 slow in response

Hi all,

I am having a little troubble with my firewall.
I have a masq'd lan behind the server and the server has iptables
setup to drop everything on input and output tables as a policy and
then specifically opens up for ports 25, 110 and so on.
The problem is that now it takes the server 10 - 30 seconds to respond
on the smtp and pop3 ports.
If I telnet to the server on port 23 there is no problem, but 25 and
110 are very slow to respond. Once the connection is established the
speed is normal though.
What gives? any clues would be helpful.
Btw, the server is running rh 7.1.
Thanks in advance.

Tobias Skytte

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