mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Frank van Maarseveen <F.vanMaarseveen@inter.NL.net>
To: linux-kernel@vger.kernel.org
Subject: 2.4.0-test11 af_packet/tcpdump/routing bug?
Date: Sun, 26 Nov 2000 00:55:38 +0100	[thread overview]
Message-ID: <20001126005538.A10587@iapetus.localdomain> (raw)

The tcpdump program (tcpdump -p -i ppp1 -s 1500 not port login) will
not report any packets after adding a default route to eth0 in the setup
below. The packet generating command is ping 192.168.2.42

It has been verified at the ppp1 peer that packets really arrive there via
ppp. Tcpdumping eth0 locally also confirms that packets don't go via eth0.

After adding/deleting the default route tcpdump needs to be restarted
to notice the difference. It uses the af_packet kernel module and maybe
its usage count must drop to zero temporarily to make a difference (I
don't know).

iapetus ~# route                     
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.2.42    *               255.255.255.255 UH    0      0        0 ppp1
192.168.0.39    *               255.255.255.255 UH    0      0        0 eth0
192.168.2.0     *               255.255.255.0   U     0      0        0 eth0
localnet        *               255.255.255.0   U     0      0        0 eth0
loopback        *               255.0.0.0       U     0      0        0 lo
iapetus ~# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:50:04:21:99:04  
          inet addr:192.168.0.39  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:34216 errors:0 dropped:0 overruns:0 frame:0
          TX packets:52668 errors:0 dropped:0 overruns:0 carrier:5
          collisions:117 txqueuelen:100 
          Interrupt:10 Base address:0x300 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16144  Metric:1
          RX packets:16037 errors:0 dropped:0 overruns:0 frame:0
          TX packets:16037 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 

ppp1      Link encap:Point-to-Point Protocol  
          inet addr:192.168.2.201  P-t-P:192.168.2.42  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:331 errors:0 dropped:0 overruns:0 frame:0
          TX packets:330 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3 

Adding a default route:
iapetus ~# route add default dev eth0
iapetus ~# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.2.42    *               255.255.255.255 UH    0      0        0 ppp1
192.168.0.39    *               255.255.255.255 UH    0      0        0 eth0
192.168.2.0     *               255.255.255.0   U     0      0        0 eth0
localnet        *               255.255.255.0   U     0      0        0 eth0
loopback        *               255.0.0.0       U     0      0        0 lo
default         *               0.0.0.0         U     0      0        0 eth0

-- 
Frank
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/

                 reply	other threads:[~2000-11-26  0:42 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20001126005538.A10587@iapetus.localdomain \
    --to=f.vanmaarseveen@inter.nl.net \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®