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HETZNER: How to setup additional IP subnet for virtualization?
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HETZNER: How to setup additional IP subnet for virtualization?

AbdessamadAbdessamad Member
edited February 2014 in Help

Hi Guys,

I hope you can help me to fix this problem

i have a server with just 1 IP from Hetzner,
so i ordered additional IP subnet

i want to use IPs for VPSes

i have Centos 6.5 in the node

and the same OS for all VPSes

and i use SolusVM+OpenVZ for virtualisation

Support sent me these links:
http://wiki.hetzner.de/index.php/Netzkonfiguration_CentOS/en

http://wiki.hetzner.de/index.php/Zusaetzliche_IP-Adressen/en

http://www.wiki.hetzner.de/index.php/Virtualisierung/en#Subnets

Can you please simplify me what to do?

all subnet IPs are unreachable even afterVPS creation

Kind Regards,

Comments

  • IncrehostIncrehost Member
    edited February 2014

    Hello, OpenVZ doesn't need any special configuration, those networks scripts should make it
    work automagically :)

    Just remember to keep the SCOPE="peer x.y.z.q" line or similar (inside your main
    interface network configuration file) for your distro so it can reach the outside world.

    Check also /etc/sysctl.conf with the OpenVZ recommended settings:

    net.ipv4.ip_forward = 1
    net.ipv6.conf.default.forwarding = 1
    net.ipv6.conf.all.forwarding = 1
    net.ipv4.conf.default.proxy_arp = 0
    net.ipv4.conf.all.rp_filter = 1
    kernel.sysrq = 1
    net.ipv4.conf.default.send_redirects = 1
    net.ipv4.conf.all.send_redirects = 0
    

    Hope it helps.

    Cheers

  • I recall others having problem and did a search but could only find this thread which may (or may not) help you: http://lowendtalk.com/discussion/comment/300859/

  • thank you @Increhost

    i have the same as you in the file /etc/sysctl.conf

    can you explain me more about this?

    Increhost said: Just remember to keep the SCOPE="peer x.y.z.q" line or similar (inside your main interface network configuration file) for your distro so it can reach the outside world.

    i have the SCOPE in the file ifcfg-eth0

    thanks in advance

  • do you see ARP requests hitting your main interface?
    also, have you erased all the other config, that it's within those tutorials? (those are mainly for XEN and KVM)

  • I didn't do any thing from those tutorials because i do not have KVM or Xen; as i mentionned: i have OpenVZ

    which documentation is the right one for me?

    @DeanClinton thanks for the link

    Regards,

  • i have these configs:

    ifcfg-eth0

    ifcfg-venet0

    ifcfg-lo

    and do not have:

    ifcfg-br0

    when i try to add IP with command:

    ip route add xx.xx.xx.xx/32 dev br0

    it says:
    Cannot find device "br0"

    do i have to change br0 in the command to venet0?

    or i have to rename venet0 to br0?

    or create a knew file called br0?

    Thanks in advance

  • iptables rules (non-SolusVM ones) ?

    ARP Requests reach the server ?

    did you check that the sysctl config is applied and running (ex: rebooted after modification)?

  • Increhost said: iptables rules (non-SolusVM ones) ?

    i didn't touch any rules,

    Increhost said: ARP Requests reach the server ?

    how to know that? buit the server main IP is pinging

    Increhost said: did you check that the sysctl config is applied and running (ex: rebooted after modification)?

    Yes Rebooted the system.

    what about my questions above @Increhost ?

    thanks for your help.

  • IncrehostIncrehost Member
    edited February 2014

    @Abdessamad said:

    do i have to change br0 in the command to venet0?

    nope

    or i have to rename venet0 to br0?

    not at all, br0 is a bridge interface, those instructions are for XEN or KVM

    or create a knew file called br0?

    nope

    you can see ARP request by doing:

    # tcpdump -i eth0 -ttttnnnNeq arp
    

    and check if you receive the "Request who-has" messages for the IP's within your subnet
    (try to ping one of them from a remote box after entering the above command).

  • AbdessamadAbdessamad Member
    edited February 2014

    Does is take too much time?

    i'm still waiting and utill now i have 6 lines as result but didn't yet finish.

  • AbdessamadAbdessamad Member
    edited February 2014

    Hi @Increhost

    until now i have:

    12 packets captured

    12 packets received by filter

    0 packets dropped by kernel

  • check the lines, and see if the IP you're pinging is there, if it is, then
    the request are reaching your box and you're not replying, what distro are you using ?

  • May i suggest ...

    sed -i 's/NEIGHBOUR_DEVS=detect/NEIGHBOUR_DEVS=all/g' /etc/vz/vz.conf

    and a reboot

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