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Excluded-Addresses

Hello Guys, I'm having trouble identifying already used addresses of the excluded-address range and the ones that are still up for grab. Is there a command I can use?.

 

Thanks.

2 ACCEPTED SOLUTIONS

Accepted Solutions
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VIP Engager

Re: Excluded-Addresses

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Hall of Fame Master

Re: Excluded-Addresses

Hello @kabambaivan06544 ,

unfortunately only the double check with ping and show ip arp can give a meaningful answer on what addresses are in use as I have explained in my previous post ( some hosts can have a SW firewall running blocking ICMP echo replies) and also you need to verify if there are powered off devices that could have one of these addresses.

 

However, unless you have issues with DHCP pool = you are using all the IP addresses in the pools this work can be done in background.

 

Hope to help

Giuseppe

 

View solution in original post

6 REPLIES 6
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VIP Mentor

Re: Excluded-Addresses

Hello,

 

you could use a broadcast ping. For Windows, the DOS command would look like below (with 192.168.1.0/24 being your network):

 

FOR /L %i IN (1,1,254) DO ping -n 1 192.168.1.%i

 

https://smallbusiness.chron.com/ping-ip-addresses-lan-68381.html

Highlighted
Hall of Fame Master

Re: Excluded-Addresses

Hello @kabambaivan06544 ,

you can use the following commands :

ping x.x.x.x

show ip arp x.x.x.x

 

Note: an existing host with IP x.x.x.x may answer to ping (in that case it exists for sure) or it may not answer if the show ip arp x.x.x.x provides a complete MAC address and not tells incomplete the IP address is in use but there is a firewall running on the host.

You need to perform this two steps procedure for all the addresses in the excluded range.

At the end you can find how many of them are alive.

 

Warning: you need to consider also the possible case that some hosts that owns an exlcuded address is powered off during your checks so you may need to go on site to check for this or to have someone to make an on site check for you.

 

Hope to help

Giuseppe

 

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Re: Excluded-Addresses

Thanks guys, but my predecessor used to use big ranges and i wouldn't like to ping through all of them. Though I think i have to settle for this long method.
Highlighted
Hall of Fame Master

Re: Excluded-Addresses

Hello @kabambaivan06544 ,

unfortunately only the double check with ping and show ip arp can give a meaningful answer on what addresses are in use as I have explained in my previous post ( some hosts can have a SW firewall running blocking ICMP echo replies) and also you need to verify if there are powered off devices that could have one of these addresses.

 

However, unless you have issues with DHCP pool = you are using all the IP addresses in the pools this work can be done in background.

 

Hope to help

Giuseppe

 

View solution in original post

Highlighted
VIP Engager

Re: Excluded-Addresses

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Re: Excluded-Addresses

Thanks People, i used the ping method.