12/2/2023 0 Comments Cisco ping sweep![]() Nmap -sn 192.168.1.104 -disable-arp-pingįrom given below image you can observe it found 1 Host is up. We can use – sn flag which means no port scan also known as ping scan. In order to identify live host without using ARP request packet Nmap utilize – sP option which is known as Ping Sweep Scan. In this article we are using - disable-arp-ping attribute for changing the behavior of nmap scans to treat a local network as a public network. ![]() If an external network is to be scanned Nmap sends following request packets:.Scanning Local Network with Nmap where nmap sends an ARP packet with every scan.Nmap scans changes their behavior according to the network they are scanning. ![]() Ping scan by default send an ARP packet and gets a response to check if the host is up. As we know that ping by default send the ICMP echo request and gets an ICMP echo reply if the system is alive. Ping scan in nmap is done to check if the target host is alive or not. It’s probably not an effective way to quickly map a subnet in everyday life.In this article we are going to scan the target machine with different Nmap ping scans and the response packets of different scans can be confirmed by analysis of Nmap traffic through Wireshark. To return to the original claim that a broadcast ping will reveal all devices in a given subnet: the conclusion is that this only goes for network devices, and not for end devices. So with limited testing I can conclude for now that it’s also just network devices that respond to ping in IPv6. But the test results are similar to IPv4: a ping to FF02::1 (‘all nodes’ multicast) does not give a single reply, but a ping to FF02::2 (‘all routers’ multicast) gives a reply from the Vyatta, which is indeed configured for IPv6 routing. ![]() Since most of my devices do not have IPv6 support for the moment (I’m planning on upgrading them in the future), I’m left with the Vyatta, Windows 7, Windows Server, and Fedora for this test. Note that I say multicast, as IPv6 has no concept of broadcast. Multicast pings would be the only feasible option to scan a subnet. A common /64 subnet is 1.8×10^19 addresses, with EUI-64 (see a perfect explanation about EUI-64 on ) you can exclude some addresses, leaving ‘just’ 2.8×10^14 possible combinations. That answers one question, but what about IPv6? Are things different there? A ping sweep is nearly impossible. So after a ping sweep, just doing ‘arp -a’ in the Windows command line reveals all managed network devices. There’s still a difference between a ping sweep and a broadcast ping, even if just done towards network devices: a ping sweep will trigger ARP requests for each address, to which devices will respond if they have the address, whether ICMP pings are blocked or not. To be sure I didn’t make a mistake, I did unicast pings after this to the addresses that didn’t respond, and they all reacted fine. The Vyatta and the ISP gateway are also network devices, but I have no control over the gateway, and the Vyatta is actually nothing more than a stripped-down Linux and thus may react as an end device in this regard. All other devices wouldn’t respond to broadcast pings. The results showed a clear separation between network devices and end devices: the Cisco gear (with the exception of the IP Phone) would respond to broadcast pings, as well as the DD-WRT. I did several tests and also changed IP addresses several times between tests to ensure ARPs were sent around the network, which made it easier to follow the captures on Wireshark. All devices received an IP address in the 192.168.0.0/24 range, the pings were done to 192.168.0.255. Contrary to Windows, IOS will list all replies received when sending to a broadcast address. I also did pings from some of the Cisco devices. I ran Wireshark on the physical machines (Windows 7 and Windows XP) from which I was going to originate the pings. – And finally, one iPod, for a total of 12 devices having an IP address. – The ISP-provided gateway: a Motorola with NAT I created a subnet with as many different devices as I could get my hand on at the time. I decided to test this out for myself and see what happened. A ping sweep is easiest, but some people claim that a simple ping to the subnet broadcast address will make all devices respond. I’ve often seen discussions of ‘how to find devices in the network using pings’.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |