Checking IP addresses

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IPmanager provides a number of functions for checking IP address availability. The procedure includes the following steps:

1) Once the IP address is released, it is not marked as free at once. First, it will get "Pending" status.

2) Once an hour (this period can be changed) a cron job is started for checking pending IP addresses.

3) If no errors are detected, it is marked as free. Otherwise, the IP will be given another status depending on the check it did not pass.

If you released an IP address for special purpose and want to reuse it before it will pass the checking procedure, you can delete this address with administrator privileges, so that the address will be marked as "free" without any additional checks.

2 types of IP address checks are currently implemented in the control panel:

  • Availability of IP address
  • IP-address is included into DNSBL blacklists

Availability of IP address

This check enables not to allocated IP addresses that are already used in the network.

To activate the check, in the configuration file specify the following path to the checking script

IpCheckerScript /usr/local/mgr5/sbin/ipchecker.sh

By default the scrip is located in /usr/local/mgr5/sbin/ipchecker.sh

The simplest example of the script for checking availability of IP address using the ping utility, may look like that

#!/bin/sh

ping -c3 -q $1 > /dev/null
if [ $? -ne "0" ]; then
    echo "OK"
fi

However ping does not guarantee 100% availability of IP address, other scripts may check routing tables on network equipment. Mind the following 2 requirement when writing a custom script:

  • the first parameter for that scrip is the IP address to be checked
  • if the IP address specified is not accessible through network and it can be allocated to users, the script must output the OK message (see example). Otherwise, the IP addresses cannot be used.

If the IP address is accessible through the network, it is marked as "problem" and will be checked again during the next check.

IP address is included into DNSBL blacklists

You can add IP addresses into black lists in the corresponding module.

If the IP address is included into a black list, it will be marked as "bad".

You can view a list of IP addresses that did not pass the checking procedure in the Problem IP addresses module, where you can release them.

To disable IPv6 check, specify the following in the configuration file

Option DisableIPv6Checking