Subject: ISDN - first TCP connection fails
To: None <tech-net@netbsd.org>
From: Ingolf Steinbach <ingolf@steinba.ch>
List: tech-net
Date: 03/08/2002 18:36:52
Hi,

on my NetBSD 1.5.3_ALPHA (i386) system with i4b 00.96.0
I have tried to set up the ISDN connection according to
http://www.de.netbsd.org/Documentation/network/isdn/
(I was told that the i4b in -current is the same as 00.96.0,
so this description should work.)

The network configuration looks like this:
# ifconfig isp0
isp0: flags=a811<UP,POINTOPOINT,SIMPLEX,LINK1,MULTICAST> mtu 1500
        inet 0.0.0.0 -> 0.0.0.1 netmask 0xff000000
        inet6 fe80::200:c0ff:fe20:6b63%isp0 -> :: prefixlen 64 scopeid 0x8
# netstat -nr -f inet
Routing tables

Internet:
Destination        Gateway            Flags     Refs     Use    Mtu  Interface
default            0.0.0.1            US          0     5062   1500  isp0
0.0.0.1            0.0.0.0            UH          0        0   
1500  isp0
127                127.0.0.1          UGRS        0        0  33228  lo0
127.0.0.1          127.0.0.1          UH          2        2  33228  lo0
192.168.2          link#1             UC          1        0   1500  we1
192.168.2.5        00:00:1c:d3:c3:13  UHLc        6    32887   1500  we1

This is the result of
    ifconfig_isp0="inet 0.0.0.0 0.0.0.1 link1 down"
    defaultroute="0.0.0.1 -iface"
in /etc/rc.conf.

No ipnat rules are installed, and ipf is disabled. But both are
enabled in the kernel config file (in case it matters).

Let's now try to connect to an external host (www.netbsd.org):
% telnet -N 204.152.186.171
Trying 204.152.186.171...
telnet: Unable to connect to remote host: Can't assign requested address

The first try to connect always fails: If I use tcpdump on isp0,
there is just some non-IP traffic (probably related to ppp).
The second try of the above telnet will usually succeed.

Am I missing something? Is this normal behaviour? How can I fix
this?

TIA
    Ingolf