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Static IP's RRS feed

  • Question

  • I am an IT Technician, we are currently in the process of switching our network from class c ip's to a class b. To broaden our scope and switch off a 1.5M pipe to 3M pipe. Thus i need a way to run a scan and find all static IP's on my network. I have already ran a report out Spiceworks and did fairly well, but there were some missing. Such as our process server, Domain controller etc. Is there a command line tool, or any program that will scan and list wether it is DHCP or static?
    Thursday, April 8, 2010 1:20 PM

Answers

  • Angry IP Scanner is a network scanning tool that might work well for you.

    That being said, I would NOT scale to a Class B subnet mask for your internal networks.  No more than 500 hosts should exist on a subnet, and this is because the broadcast traffic created by these hosts would degrade network performance.  Consider instead creating an additional subnet, and implement a router to pass traffic between the new and existing subnets.  The biggest subnet you should use is a 23-bit subnet mask, which results in 510 usable hosts, as two are reserved for the network address and broadcast address.  Warning: Using a 23-bit subnet mask requires classless inter-domain routing (CIDR), and all network hardware and software must support it.  Otherwise, if you use a Class C internal subnet, such as 192.168.1.0, the networks will be split into two.  This should not be an issue.  Consider reorganizing your hosts into blocks instead.  Perhaps servers could exist in a block of 100 addresses, printers in a block of 20, and clients in a block of 100.  That would give you 34 hosts to play with if you fill one address block.

    Also, please bear in mind that any device with a firewall may not show up on any network scanner, and many intrusion detection/prevention systems may flag an alert.  If an IP address is DHCP assigned, you should be able to export this information from the DHCP console by viewing address leases.

    • Proposed as answer by Rabid Squirrel Friday, April 9, 2010 5:40 PM
    • Marked as answer by Kevin Remde Sunday, April 11, 2010 1:07 PM
    Friday, April 9, 2010 5:39 PM
  • Wouldn't your static IP addresses be reserved in your DHCP server?  If not, they'd at least be excluded from your IP ranges, yes?  That's not a complete solution but might give you a head start to determining if you're missing a few.  You could then ping those specified addresses and see what comes up - if you're lucky they're registered in DNS and their name will be reported.

    I don't have a tool right to mind for you but this is a great example of why you need to document your network, especially static IP addresses, so that you already know what machines have what addresses.


    -B-
    http://www.officeforlawyers.com
    Author: The Lawyer's Guide to Microsoft Outlook
    • Marked as answer by Kevin Remde Sunday, April 11, 2010 1:07 PM
    Thursday, April 8, 2010 5:27 PM

All replies

  • Wouldn't your static IP addresses be reserved in your DHCP server?  If not, they'd at least be excluded from your IP ranges, yes?  That's not a complete solution but might give you a head start to determining if you're missing a few.  You could then ping those specified addresses and see what comes up - if you're lucky they're registered in DNS and their name will be reported.

    I don't have a tool right to mind for you but this is a great example of why you need to document your network, especially static IP addresses, so that you already know what machines have what addresses.


    -B-
    http://www.officeforlawyers.com
    Author: The Lawyer's Guide to Microsoft Outlook
    • Marked as answer by Kevin Remde Sunday, April 11, 2010 1:07 PM
    Thursday, April 8, 2010 5:27 PM
  • Angry IP Scanner is a network scanning tool that might work well for you.

    That being said, I would NOT scale to a Class B subnet mask for your internal networks.  No more than 500 hosts should exist on a subnet, and this is because the broadcast traffic created by these hosts would degrade network performance.  Consider instead creating an additional subnet, and implement a router to pass traffic between the new and existing subnets.  The biggest subnet you should use is a 23-bit subnet mask, which results in 510 usable hosts, as two are reserved for the network address and broadcast address.  Warning: Using a 23-bit subnet mask requires classless inter-domain routing (CIDR), and all network hardware and software must support it.  Otherwise, if you use a Class C internal subnet, such as 192.168.1.0, the networks will be split into two.  This should not be an issue.  Consider reorganizing your hosts into blocks instead.  Perhaps servers could exist in a block of 100 addresses, printers in a block of 20, and clients in a block of 100.  That would give you 34 hosts to play with if you fill one address block.

    Also, please bear in mind that any device with a firewall may not show up on any network scanner, and many intrusion detection/prevention systems may flag an alert.  If an IP address is DHCP assigned, you should be able to export this information from the DHCP console by viewing address leases.

    • Proposed as answer by Rabid Squirrel Friday, April 9, 2010 5:40 PM
    • Marked as answer by Kevin Remde Sunday, April 11, 2010 1:07 PM
    Friday, April 9, 2010 5:39 PM
  • Thanks for your input. I have Angry IP it doesn't list wether it is static or not. I have also tried Zenmap very useful but still does not tell me what i need. I have ran a few reports out of spiceworks that has given me the majority of the statics. But i am missing a few critical ones and makes me wonder if i am missing more. I also ran one for DHCP. I can compare the two just didn't want to go thru the paperwork.

     

    Thanks.

    Tuesday, April 13, 2010 8:14 PM
  • Looking back all the post.. is interesting to see this forum have grow

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