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Interfaces that receive but don't send.



Hello,

I'm trying to get an old 486 to run OpenBSD 2.9, and I'm having problems with
one of my Ethernet interfaces.  This 486 (yvonne) has two Ethernet cards: ne0
and ep1.  I've assigned ep1 the address 192.168.0.5.  ne0, in the long run,
will be configured via DHCP; I've tested that and it works.  For the moment,
I've connected it to the local network and assigned it the IP 192.168.0.42.
The other machines on the network are gauss (192.168.0.3) and pepe
(192.168.0.2).  gauss, pepe, and both of yvonne's interfaces are connected
to the same hub.  pepe and gauss can ping each other as you would expect.
However, neither of them can ping either of yvonne's interfaces, and yvonne
cannot ping either of them.

If I ping gauss from yvonne, gauss sees:

12:29:30.862478 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:30.862521 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:31.867058 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:31.867075 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:32.876969 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:32.876987 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:33.887024 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:33.887037 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:34.897078 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:34.897099 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9

On ne0, yvonne sees:

12:29:16.022491 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:16.022652 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:17.027018 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:17.027165 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:18.036932 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:18.037072 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:19.046982 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:19.047126 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9
12:29:20.057040 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:20.057182 arp reply 192.168.0.3 is-at 0:1:3:1a:a5:c9

On ep1, yvonne sees:

12:29:16.022201 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:17.026795 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:18.036710 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:19.046767 arp who-has 192.168.0.3 tell 192.168.0.5
12:29:20.056821 arp who-has 192.168.0.3 tell 192.168.0.5

When I do netstat -f inet -r on yvonne, I get:

Routing tables

Internet:
Destination        Gateway            Flags     Refs     Use    Mtu  Interface
loopback           localhost          UGRS        0        0  32972  lo0
localhost          localhost          UH          2      179  32972  lo0
192.168/16         link#2             UC          0        0   1500  ep1
yvonne             localhost          UGHS        0        9  32972  lo0
BASE-ADDRESS.MCAST localhost          URS         0        0  32972  lo0

So it looks like ne0 can send and receive, and ep1 can only send.  Since
yvonne routes 192.168/16 through ep1, the arp replies never reach her.  I
decided to test this, so I modified the routing tables to make 192.168/16 go
through ne0.  Everything was consistent with how it acted before: ne0 sent
an arp request, received an arp reply, sent echo requests, and received echo
replies, while ep1 saw nothing (since it wasn't sending anything and couldn't
receive anything).

I guessed that it might be a bad cable, so I restored the routing tables to
their original state and swapped ep1's and ne0's cables.  I got the same
result.  ep1 still could not receive anything, and ne0 worked fine.

I doubt that ep1 is failing.  If so, it would have had to have stopped working
exactly when I began installing OpenBSD and not a moment before.  It's
possible, but unlikely.

That leaves a configuration or driver problem.  I doubt it's the drivers.
ifconfig ep1 tells me:

ep1: flags=8863<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        media: Ethernet 10baseT
        inet 192.168.0.5 netmask 0xffff0000 braodcast 192.168.255.255
        inet6 fe80::2a0:24ff:fe1b:e15%ep1 prefixlen 64 scopeid 0x2

hostname.ep1 is:

inet 192.168.0.5 255.255.0.0 NONE

At the moment, I'm out of ideas, and I'm rather frustrated.  I'm guessing that
I've made a simple error somewhere, but I don't know what it is.  I'd
appreciate help, if possible, or a pointer to something that tells me what
I've missed.  Thanks.

-- 
Kyle R. Hofmann <krh_(_at_)_lemniscate_(_dot_)_net>



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