Re: Strange networking issue

From: Bruce Zimmer (b.r.zimmer@WORLDNET.ATT.NET)
Date: Fri Apr 25 2003 - 09:06:52 EDT


Yes same subnet, but what subnet is the 10/100 interface on. If they
are both on 170.29.112/24 then the packet will go from 170.29.112.254 to
170.29.112.30, but the return packet will exit the AIX machine from
170.29.112.xxx (the 10/100 interface) and if the 10/100 and gig are not
on the same physical network the packet will never get back to the Win2K
gig interface. To fix that set up a static route on the AIX box.

route add -host 170.29.112.254 -netmask 255.255.255.255 170.29.112.30

Bruce Zimmer
Central Data Systems
(248) 615-4644 (direct)
(248) 320-1175 (cell)
bzimmer@centraldata.com

-----Original Message-----
From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On Behalf Of
Willeat, Todd
Sent: Friday, April 25, 2003 12:56 AM
To: aix-l@Princeton.EDU
Subject: Re: Strange networking issue

There shouldn't be any routing since both boxes are on the same
subnet...
But, if it helps, here's the traceroute info:

trying to get source for mhp-aquaman
source should be 170.29.112.254
traceroute to mhp-aquaman (170.29.112.30) from 170.29.112.254
(170.29.112.254), 30 hops max
outgoing MTU = 1500
 1 * * *
 2 * * *
 3 * * *
 4 * * *
 5 * * *
 6 * * *
 7 * * *
 8 * * *
 9 * * *
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * * *
23 * * *
24 * * *
25 * * *
26 * * *
27 * * *
28 * * *
29 * * *
30 * * *

-----Original Message-----
From: John Jolet [mailto:john.jolet@FXFN.COM]
Sent: Thursday, April 24, 2003 8:16 PM
To: aix-l@Princeton.EDU
Subject: Re: Strange networking issue

really, really sounds like a routing issue...what does a traceroute from
the
aix to win2k box look like?

-----Original Message-----
From: Willeat, Todd [mailto:TWilleat@MHP.SMHS.COM]
Sent: Thursday, April 24, 2003 5:22 PM
To: aix-l@Princeton.EDU
Subject: Strange networking issue

Hi all,

I have a strange network connectivity issue between a p640 box (AIX
4.3.3
ML11) and a Win2K box (SP3). Both boxes are on the same subnet (and same
switch), but are having problems pinging each other. The Win2K box has
no
problem connecting to other boxes, and people can telnet to the AIX box.
The
Win2K box has 6 GigE connections in an 802.3ad dynamic team. The p640
box
has a SysKonnect dual-port GigE card running in failover mode (as well
as
the 2 integrated 10/100s - I have one of these on another subnet and the
Win2K box can ping that just fine...). Looking at the arp tables shows
that
each box knows the other's MAC address. My network admin captured some
packets between the 2 and this is what we saw:

Pinging from Win2K to AIX - we saw the packet go from Win2K to AIX, but
AIX
did not return any packets.
Pinging from AIX to Win2K - we saw the packet go from AIX to Win2K and
saw
the response packet from Win2K to AIX, but AIX did not receive it
(request
timed out).

It appears that AIX is dropping the packets from this Win2K box for some
reason (I have several other p640s with the same config that work fine).
However, when I rebooted the Win2K box (after it locked up...), I could
then
ping between the boxes. But this only lasted for a day or so, and now it
is
not working again.

Has anyone seen anything like this before?

               _______________________________________
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