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#!/bin/bash
 
let r=1
let k=1
 
for i in `cat veids`
do
    numips=$(sed -n "$k"p numips)
        for (( c=1; c<=$numips; c++ ))
          do
                ip=$(sed -n "$r"p newips)
                echo "Add $ip to $i"
                vzctl set $i --ipadd $ip --save
                let r=r+1
        done
    let k=k+1
done

Hopefully this will help any others who run into a similar issue.

Have a great day!

Today I ran into an interesting issue where a VPS had no networking either inbound or outbound after setup. This is the error that would present when restarting network via init.d:

Bringing up interface venet0:
SIOCADDRT: Network is unreachable
SIOCADDRT: Network is unreachable

This issue also presented in that cPanel licenses could not activate not could any ping or host commands work properly. I eventually narrowed down the issue to the fact that the IPs that had been added to the VPS were not properly set to ARP by checking with the following command (run on the node):

arp | grep [INSERT IP HERE]

In order to resolve this, all I needed to do was add the arp entries for the IPs on the actual virtual environment by running the following commands on the node:

arp -s [INSERT IP HERE] `ifconfig eth0 | grep eth0 | awk '{print $5}'` pub

Make sure you run the command above for every IP on the VPS. This resolved the issue and all networking started working again properly.

1. Empty out the contents of /etc/sysconfig/iptables

   cat "" > /etc/sysconfig/iptables

2. Use the following line in /etc/sysconfig/iptables-config:

   IPTABLES_MODULES="ipt_REJECT ipt_tos ipt_TOS ipt_LOG ip_conntrack ipt_limit ipt_multiport iptable_filter iptable_mangle ipt_TCPMSS ipt_tcpmss ipt_ttl ipt_length ipt_state iptable_nat ip_nat_ftp"

3. Use the following line in /etc/vz/vz.conf:

   IPTABLES="ipt_REJECT ipt_tos ipt_limit ipt_multiport iptable_filter iptable_mangle ipt_TCPMSS ipt_tcpmss ipt_ttl ipt_length ipt_state"

After ensuring these three things, just stop both vz and iptables, start iptables, then start vz. You should then be able to use iptables within a virtualized container.

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#!/bin/bash
for i in `vzlist -a | grep -v CTID | awk '{print $1}'`
do
     let k=0
     for j in `cat /root/ips`
     do
          if [ $k -lt 2 ]
          then
               vzctl set $i --ipadd $j --save
               let k=k+1
          else
               sed -i '1,2d' /root/ips
               break
          fi
     done
done

The main things to note here are the following:

• When assigning a variable a value in a for loop, you need to use “let” before declaring it
• SED can be used to remove lines just as it can be used to add and replace items in lines
• Break is not something to be afraid of!

In any case, this script might be handy for others trying to perform similar tasks so I’ll just leave it here. Feel free to modify and use this code as you please Let me know if you have any optimizations you can think of in the comments below.