[Users] [Debian] VE network isolation

spameden spameden at gmail.com
Mon Aug 19 17:23:29 EDT 2013


The problem here is actually much wider..

I can access any of the venet0 assigned IP address from the container via
lo interface.

E.g. if I have another container with an IP address of 1.2.3.4 I can access
it through lo interface from this container.


2013/8/20 spameden <spameden at gmail.com>

>
>
>
> 2013/8/20 Ola Lundqvist <ola at inguza.com>
>
>> Hi
>>
>> It all depends on how you have done things. There are a few things
>> that is not fully clear that you should probably add in a forum
>> question.
>>
>> You mention that you use both venet and veth devices. It
>> is not clear what you use in this situation.
>> (To my knowledge only veth makes sense to use with vzbr).
>>
>
> Yes, I'm using both devices.
>
> I've added veth device to the vzbr201 device with private IP address, e.g.
> 192.168.201.2.
>
> venet0 is used for public internet address, e.g. 1.2.3.4
>
>>
>> It is also not clear how you add veth to the bridge.
>>
>
> I'm adding it via /etc/vz/vznet.conf:
>
> #!/bin/bash
> EXTERNAL_SCRIPT="/usr/sbin/vznetaddbr"
>
>
>>
>> I guess you have read this article:
>> http://openvz.org/Virtual_Ethernet_device
>>
>
> Did already.
>
>
>>
>> Also it may be so that even though you have added them to
>> different bridges, then the bridges may be connected to something
>> common. It is not clear from the text below.
>>
>
> How bridges can be connected to the same thing if they are different?
>
>>
>> Hope this helps for your forum question.
>>
>> Cheers,
>>
>> // Ola
>>
>>
>> On Tue, Aug 20, 2013 at 12:53:23AM +0400, spameden wrote:
>> >    Yes, I have forwarding turned on.
>> >    # sysctl -a 2>/dev/null|grep ip_forward
>> >    net.ipv4.ip_forward = 1
>> >    Surely, I can try to ban this via iptables, but it's so much hassle
>> to
>> >    ban each time.
>> >    I thought it should "work out out of the box"..
>> >    Anyways, thanks for your point, I will try to post this on forums.
>> >
>> >    2013/8/20 Ola Lundqvist <[1]opal at debian.org>
>> >
>> >      Hi
>> >      This kind of question belong more on the openvz forum
>> >      [2]http://forum.openvz.org/.
>> >      Please ask there.
>> >      However I think it is not worwarded through "lo", instead I guess
>> >      you
>> >      have IP forwarding turned on in the kernel and as the kernel gets
>> >      aware
>> >      of those datagrams it will forward it to the correct place. To
>> >      prevent
>> >      that I guess you have to add some firewalling rules (see iptables).
>> >      But again, this better belong on the forum, and I may be totally
>> >      wrong.
>> >      Cheers,
>> >      // Ola
>> >
>> >    On Tue, Aug 20, 2013 at 12:04:42AM +0400, spameden wrote:
>> >    >    Hi, list.
>> >    >    I'm sorry for copying 2 lists, but I really want to know what
>> I'm
>> >    doing
>> >    >    wrong.
>> >    >    I'm using Debian 6 Squeeze and OpenVZ CentOS kernel (converted
>> >    from rpm
>> >    >    to deb).
>> >    >    I'm using veth as well as venet devices for networking.
>> >    >    To isolate multiple containers from each other I'm using vzbrXXX
>> >    >    devices on debian like this:
>> >    >    auto vzbr203
>> >    >    iface vzbr203 inet static
>> >    >            address 192.168.203.1
>> >    >            netmask       255.255.255.0
>> >    >            broadcast       192.168.203.255
>> >    >            bridge_ports none
>> >    >            bridge_fd 0
>> >    >            bridge_maxwait 0
>> >    >    auto vzbr202
>> >    >    iface vzbr202 inet static
>> >    >            address 192.168.202.1
>> >    >            netmask       255.255.255.0
>> >    >            broadcast       192.168.202.255
>> >    >            bridge_ports none
>> >    >            bridge_fd 0
>> >    >            bridge_maxwait 0
>> >    >    The problem I'm facing that in VE (for example with CTID 202) I
>> >    can
>> >    >    ping or query 192.168.203.1 which is on HN of course, but I
>> >    thought it
>> >    >    shouldn't be reachable.
>> >    >    Here is route table and ifconfig on CTID 202:
>> >    >    # ip r
>> >    >    default dev lo  scope link
>> >    >    # ifconfig -a
>> >    >    lo        Link encap:Local Loopback
>> >    >              inet addr:127.0.0.1  Mask:255.0.0.0
>> >    >              inet6 addr: ::1/128 Scope:Host
>> >    >              UP LOOPBACK RUNNING  MTU:16436  Metric:1
>> >    >              RX packets:84021 errors:0 dropped:0 overruns:0 frame:0
>> >    >              TX packets:84021 errors:0 dropped:0 overruns:0
>> carrier:0
>> >    >              collisions:0 txqueuelen:0
>> >    >              RX bytes:5045068 (4.8 MiB)  TX bytes:5045068 (4.8 MiB)
>> >    >    venet0    Link encap:UNSPEC  HWaddr
>> >    >    00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
>> >    >              BROADCAST POINTOPOINT NOARP  MTU:1500  Metric:1
>> >    >              RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>> >    >              TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>> >    >              collisions:0 txqueuelen:0
>> >    >              RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
>> >    >    So I guess it's going through lo device? Why and how can I block
>> >    this?
>> >    >    Many thanks.
>> >
>> >      > _______________________________________________
>> >      > Debian mailing list
>> >      > [3]Debian at openvz.org
>> >      > [4]https://lists.openvz.org/mailman/listinfo/debian
>> >      --
>> >       --------------------- Ola Lundqvist ---------------------------
>> >      /  [5]opal at debian.org                     Annebergsslingan 37
>>  \
>> >      |  [6]ola at inguza.com                      654 65 KARLSTAD
>>  |
>> >      |  [7]http://inguza.com/                  +46 (0)70-332 1551
>>   |
>> >      \  gpg/f.p.: 7090 A92B 18FE 7994 0C36  4FE4 18A1 B1CF 0FE5 3DD9 /
>> >       ---------------------------------------------------------------
>> >
>> > Referenser
>> >
>> >    1. mailto:opal at debian.org
>> >    2. http://forum.openvz.org/
>> >    3. mailto:Debian at openvz.org
>> >    4. https://lists.openvz.org/mailman/listinfo/debian
>> >    5. mailto:opal at debian.org
>> >    6. mailto:ola at inguza.com
>> >    7. http://inguza.com/
>>
>> --
>>  --- Inguza Technology AB --- MSc in Information Technology ----
>> /  ola at inguza.com                    Annebergsslingan 37        \
>> |  opal at debian.org                   654 65 KARLSTAD            |
>> |  http://inguza.com/                Mobile: +46 (0)70-332 1551 |
>> \  gpg/f.p.: 7090 A92B 18FE 7994 0C36 4FE4 18A1 B1CF 0FE5 3DD9  /
>>  ---------------------------------------------------------------
>>
>
>
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