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Questions tagged [nmap]

Nmap (Network Mapper) is a security scanner originally written by Gordon Lyon (also known by his pseudonym Fyodor Vaskovich) used to discover hosts and services on a computer network, thus creating a "map" of the network.

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Best way to determine if IPs in a subnet are up or down in Linux

I have a simple method that I am using on four subnets to determine which registered IPs are actually up and active, and which ones can be removed. Initially, I iterate through the list of domain names with this command: sudo nmap -sS -O -v oN…
UnworthyToast
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NMAP (or other) continuous port scan until it returns open?

Is there a way with nmap or anything else to do a continuous port scan, say on port 22, until the service comes up and the port is coming back as open? Kind of like you may have an infinite ping going, timing out, to see when a host comes back…
TryTryAgain
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Completely getting rid of SSLv3 on Apache

Our security team is asking that we completely disable SSLv3 on some of our servers running Apache. I've used the SSLProtocol entry in the ssl.conf file (like SSLProtocol ALL -SSLv2 -SSLv3) and various SSLCipherSuite entries to try to disable this…
Stefan
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Nmap external scan shows port open, ASA says port is not open, but do get an socket

Folks, have a weird one, need your expert help. For one of our heavily used external facing server which came up in an audit, nmap -Pn scan shows the following: Starting Nmap 5.51 ... Host pub.ip is up (0.0032s latency). Not shown: 993…
user3196304
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Fastest way to scan all hosts that are online

I am looking to find all the hosts that are online in a set of networks. I would like to find all hosts that are online in the entire network of 170.10.. (there are ~64K possible hosts). The network I am trying to scan is an internal local…
P.P
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nmap and arp-scan inconsistent IP-MAC results

I seem to get variable and inconsistent results for the IP/MAC addresses from a particular machine, using nmap or arp-scan. The machine has 3 interfaces, and this is what it shows: $ uname -a Linux showstore-81 2.6.35.13 #1 SMP PREEMPT Thu Feb 9…
mivk
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Scan for connected, powered on computers on a network?

I want to scan for powered on computers on my LAN and gather logs about that. I tried nmap but it didn't work very well (a lot of switched on computers are not getting detected). nmap -sP 192.168.2.0/24 Nmap done: 256 IP addresses (10 hosts up)…
Jorge Suárez de Lis
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Command line tools for ping HTTP?

Background : It's a common question as we can search at google "ping works but http does not" ping is not a reliable test of network connectivity. ping working just means enough of the IP stack is up to process ICMP Echo requests (that's not a huge…
Md Mahbubur Rahman
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Using nmap to scan open ports. iptables default policy affects other rules?

I'm trying to find out why changing my default iptables policy is affecting what nmap sees when it scans my host. Consider the following iptables setup: iptables -F iptables -A INPUT -p tcp -s 10.1.0.0/20 --dport 22 -j ACCEPT iptables -P INPUT…
Ation
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Automatic/scheduled check for open ports on list of servers

I need a way to configure a scheduled check for open ports on a list of servers and to get notified if something has changed from last check. what's the best way to do it? If there is some solution which talk with Nagios it would be even better.
SecondThought
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Fast ARP scan in address-less DAD (Duplicate Address Discovery) mode

I am developing system for detecting network actual state. One part is to get all IPs and their respective MAC addresses. Right now I am using arping in DAD (Duplicate Address Discovery) mode. I send arping for every possible IP in the ranges that…
Radek Hladík
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Removing new fingerprint detection message from nmap

I run a nmap scan of my hosts daily to check for open ports. sudo nmap -f -sS -sV --log-errors -append-output -p1-9999 host.com But along with the output I get a long list of fingerprint submissions for unrecognized ports like this…
Quintin Par
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nmap reports host up when it isn't

On an Ubuntu VMWare VM I ran: sudo nmap -sP 192.168.0.* This returned: Starting Nmap 5.00 ( http://nmap.org ) at 2010-12-28 22:46 PST Host 192.168.0.0 is up (0.00064s latency). Host 192.168.0.1 is up (0.00078s latency). Host 192.168.0.2 is up…
martianway
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Finding XP boxes on our intranet

We're out on a mission to find and eradicate XP boxes on our intranet. Now we're wondering what the fastest (scan) method might be --XP boxes connected to our active directory have already been identified, but now we need to find the remaining,…
Ralf Hildebrandt
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nmap reports IP address is active, when the network device is turned off?

I want to remotely examine if some servers are up. I don't use the ping command because it gives a lot of wrong results like "destination host unreachable" and "request Timed out" due to bad networking infrastructure. I try to use nmap command to…
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