Latest LQ Deal: Latest LQ Deals
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 11-06-2014, 08:29 PM   #1
LQ Newbie
Registered: Jul 2012
Posts: 9

Rep: Reputation: Disabled
Question global ip address packets don't pass from tap interface to the virtual machine

hi, i have a config:
p6p1(physical nic, connected to isp with no addr promisc) -> pppbr0 (bridge with no addr promisc) -> tap0 (with no addr promisc connected to a vm)

iptables configured:
iptables -A FORWARD -i p6p1 -j ACCEPT
iptables -A FORWARD -o p6p1 -j ACCEPT
and same rules for pppbr0 and tap0

vm configured with a static ip, provided by an isp: gw

vm with a route:
-net gw is the ISP's NAT and a DNS server.

when I ping from a vm to the 172.16 subnet all pings traverse all the way to the vm (I receive replies)
when I ping any global ip internet, don't get any replies back.
when I monitor p6p1, pppbr0 and tap0 for the global internet ip address, being pinged with tcpdump, I see that I get reply packets from those addresses
when I tcpdump on eth0 in vm, and grep for that same address, it shows nothing.

when I stop tcpdump, it shows the line:
[so many] packets dropped by interface

I've monitored with the tcpdump, and saw, that they get all the way to the tap0 interface, the vm is connected to, but drop somewhere between tap0 of the host and eth0 of the guest.

tcpdump on the guest shows nothing about the global addresses being pinged, but when I stop tcpdump, it displays that so many packets were dropped by interface.

can anyone suggest, what blocks packets?

Last edited by igoryonya; 11-09-2014 at 09:50 AM. Reason: fix typos and add more information


bridge, tap

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
how to setup tap networking for running virtual machine? flyxtop Linux - Server 0 09-19-2014 01:44 PM
Configuring TUN/TAP for a virtual machine slakwarebunny Linux - Networking 2 06-14-2008 07:37 AM
Packets just don't reach eth interface g00nie Linux - Networking 2 02-17-2006 09:11 AM > Forums > Linux Forums > Linux - Networking

All times are GMT -5. The time now is 05:50 PM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration