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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Weird Port scanning results using nmap

I was scanning one of my friends servers using nmap and got these port details. PORT STATE SERVICE 22/tcp open ssh 42/tcp filtered nameserver 80/tcp open http 111/tcp open ...
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1k views

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 ...
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1answer
832 views

NMap route determination on Windows 7 x64 [closed]

C:\Windows\system32>nmap --iflist Starting Nmap 6.01 ( http://nmap.org ) at 2012-08-31 06:51 Central Daylight Time ************************INTERFACES************************ DEV (SHORT) IP/MASK ...
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2answers
155 views

Ubuntu 12.04 slow reply to nmap

We've upgraded some of our servers to 12.04 recently, and i've noticed that when I run nmap from some other server to check open ports on these 12.04 servers it take WAY longer than before. is this a ...
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3answers
1k views

How to list down hosts with nmap 5.51

I was using nmap 5.21 with the -PN, -F and --reason flags in version 5.21. I was outputting the results to an XML file. It would list ALL hosts (say I gave it a /24 subnet to scan. I then updated ...
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1answer
415 views

Powershell and NMAP Information Sharing

I am working on a project where I would like to perform host documentation for a variety of items. Part of these items would be sourced from Powershell and the rest would be sourced from NMAP. For ...
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2answers
251 views

pingdom like service to constantly monitor my firewall open ports

I have pingdom setup to constantly make sure my websites are up and let me know when they are not. Is there a similar service that will constantly monitor my firewall externally, and let me know when ...
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2answers
2k views

Nmap not scanning all ports

I've noticed that nmap only scans a bunch of known ports, and the only way i've managed to check 'em all is to put a "-p 0-65535" in. Why is that? am I wrong? is there a more popular way to scan all ...
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1answer
253 views

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 ...
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4k views

nmap does not find alive hosts with ping scan

I try to ping scan my local network using nmap, but it doesn't seem to find machines that are for sure alive. It responses to ping but on to ping scan. Results for ping: $ ping 192.168.0.2 PING ...
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145 views

646/tcp open unknown

when I make nmap localhost I get PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 111/tcp open rpcbind 631/tcp open ipp 646/tcp open unknown what is the port 646 ?
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568 views

What's the difference between http-proxy and ccproxy-http?

Good day, After execution command nmap -p 8080 myserver.address I've got this message PORT STATE SERVICE 8080/tcp filtered http-proxy And aftar nmap -p 808 myserver.address I've got PORT ...
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3answers
785 views

Can't Ping host, nmap detects it?

I have a simple question that I'm trying to wrap my head around. I know this requires knowledge of my internal network, but at a glance, what do you guys think.. I cannot ping a host in my network ...
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569 views

While using Nmap and sweep the network with a ping

I'm studying up on using Nmap, and there is a command that sweeps the network with a simple Ping scan to determine which hosts are online. The command is this: 1 [ignore_this]# nmap -sP 10.0.0.0/24 ...
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1answer
4k views

finding live hosts with nmap

I'm trying to find live hosts on the network with nmap: nmap -sP 192.168.3.0/24 Starting Nmap 5.21 ( http://nmap.org ) at 2012-04-10 10:28 EEST Nmap scan report for km-localhost (192.168.3.1) ...
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2answers
352 views

IP ID Sequence Generation

Perchance someone could explain me or give point me in the right direction to achieve understanding of "Busy server or unknown class" in the nmap output? "IP ID Sequence Generation: Busy server or ...
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1answer
409 views

Why is nmap now taking a long time to perform subnet ping? [closed]

I've been using the nmap tool on my Windows machine to ping my Uni house home network range using the following command: nmap 192.168.1.0/24 -sn I had no problems with this and it was only taking ...
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2answers
1k views

IPtables: is there a minimum UDP packet size for a DNS lookup?

IPtables for a virtual dedicated server. I would like to block UDP scans and I was wondering whether there's a minimum packet size for a DNS lookup? Nmap sends 0-byte UDP packets (source : ...
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2answers
960 views

Port is open on machine A but it is not visible from machine B in Nmap

I have a virtualized CentOS machine with a software that is listening on port 8080. I have turned off SELinux and flushed all iptables (so now there are no rules set). I have checked with netstat -nap ...
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5answers
11k views

How to find out that SMTP server is in open relay?

I used nmap for network security testing. It found that SMTP server was in open relay. Here is the output: nmap --script smtp-open-relay testwww.confidesk.com PORT STATE SERVICE 25/tcp open ...
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3answers
200 views

Windows Server 2008 Standard, firewall disabled by Group Policy but ports are still filtered

Hihi, So vanilla install of WS2008R2S, disabled FW with GP and trying grab SNMP with another host on the same subnet. The output of both if/ipconfig's and nmap -p 161 is below. Both machines running ...
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1answer
337 views

Detecting network state with arping

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 ...
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208 views

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 ...
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451 views

Nmap / Batch: alert if only ports usually closed are opened?

Context I check open ports on my server with a scheduled batch file: nmap.exe server1 server2 server3 etc >> log.txt Usually 21, 22, 80, 443 and 3389 are opened. Now I want to send an email ...
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45 views

Managing the Network from a linux machine

I am using Linux at my work, and i am kind of a sys admin / IT support, (not exactly my title but i do this kind of things since there is no one else). There are mostly Windows user in my organization ...
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183 views

nmap external localhost with iptables

I have a status monitor that I wish to set up using nmap to show all my externally open ports. Naturally nmap came to mind. Unfortunately I use an iptables firewall and allow all traffic on the ...
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3k views

iptables has port 80 open but nmap shows it closed

I'm having some troubles getting a Debian webserver to open up port 80 for HTTP traffic. In my iptables, I opened up port 80 using the following commands: iptables -A INPUT -p tcp --dport 80 -j ...
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1answer
133 views

Identify where a port is blocked

I'm trying to find out where a port is being blocked by a firewall; either en-route to a host or by the host itself. If I run nmap I can see that the port is filtered. However, this could mean by the ...
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1answer
668 views

Running nmap over vpn on Mac OS X 10.7 Lion fails

When connected to VPN (I have used OpenVPN and TunnelBear VPN service) nmap stops working. Ping, nc and other network tools work however nmap doesnt. When not running vpn, I get: $ sudo nmap ...
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2answers
200 views

Why is my IMAP port not showing as open ( yet it works? )

Ive recently setup Postfix and Dovecot IMAP on a Debian Lenny box. Sending to this domain works fine and reading the email via IMAP works fine too. I'm curious though as to why when running nmap, port ...
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1answer
210 views

Process killing trouble

I am trying to program a server software which involves a lot of testing on java / scala platform. Whenever i compile and execute the code. It starts listening on port 80. Sometimes i need to ...
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786 views

Block nmap xmas scan from detecting my server's open port

I have blocked all the basic nmap scans using iptables by making a rule in the INPUT chain that if the no of packet send from a particular ip within 10 seconds exceeds a particular limit then put that ...
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1answer
227 views

Allow nmap advanced scans for a normal user

I want to allow a normal user to run NMAP's advanced scans like XMAS, TCP FIN, TCP NULL scans. Can somebody please tell me how to do that ?? Since it uses raw packets so whether setting the setuid bit ...
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2answers
576 views

Cannot connect from Linux to SQL Server through a firewall

I need to connect from a Debian GNU/Linux webserver to an SQL Server database which is hosted on a Windows machine within an organization's local network. The person in charge of the database server ...
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1answer
179 views

Nmap reporting incorrect results from an idle scan

I have a VPS that I was scanning to make sure everything is in check. A regular SYN scan reports that ports 25 and 80 are open (which they should be). When I run an idle scan however, I get back that ...
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3k views

Is Telnet Port Open For The Range IP?

I want to port scanning on telnet port in a range ip . for ex: i want to know is the 23 port open on 127.0.0.1/255 ? what am i going to do ? is there a option for Nmap to do this ? Thanks .
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1answer
2k views

Why does nmap report different results from localhost?

When I execute "nmap -sT -O localhost" per the Centos 5 deployment guide, I get: Not shown: 1677 closed ports PORT STATE SERVICE 22/tcp open ssh 80/tcp open http 8080/tcp open http-proxy ...
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0answers
544 views

nmap port scan for vpn and proxies

I am trying to detect the vpn and proxies from the iplist so is anyone know the fastest and reliable scan command for nmap? right now I am using this nmap -sS -sU -T4 -A -v -PE -PP ...
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4answers
1k views

iptables rule to drop SYN and FIN attacks

From a Trustwave report, we are trying to set our server to block this type of request but after trying several combinations of rules, we can still see the ports. Could anyone give me a hint or the ...
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5answers
3k views

Can't get nmap to work under Windows 7 64 bit

I'm trying to install and run the nmap tool to test my server, but it keeps saying Note: Host seems down. If it is really up, but blocking our ping probes, try -P0 and showing all the server ports ...
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2answers
354 views

Does nmap work with ipv6?

Does nmap work with ipv6? I don't even really know if ports are handled in the same way on ipv6 so I just wondered.
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1answer
256 views

use of nmap clogged my network

I was using nmap to scan the mac addresses of my network.What I found was internet connections and rest of network services badly clogged the users were not able to connect to internet.After messing ...
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325 views

how do I scan all computers in my network with nmap?

I am trying to use nmap to scan the computers on my network for conficker. I am using Windows. What do I put in the target for all computer on a given subnet? It is running: nmap -T4 -A -v I put ...
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2answers
259 views

Command or utility to measure the amount of traffic generated by an nmap scan

First, just a bit of background: My ISP has decided to block all inbound connections (from their customers' perspective) which effectively means that I can no longer host anything on my connection ...
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444 views

different nmap results

Hello I have a scan on my server form outside and from inside, why results are different? [root@xxx ~]# nmap -sV -p 0-65535 localhost Starting Nmap 5.51 ( http://nmap.org ) at 2011-02-16 07:59 MSK ...
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1answer
209 views

NMap - running as root yields different response than running as another user

nmap -eeth1 [hostname] -p80 Running that command as root uses interface one and fails as expected (interface one is on a subnet blocked by the host.) Using interface 0 succeeds as it should. ...
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491 views

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 ...
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101 views

Network audit tracker

I'm looking for a tool like PBNJ (http://pbnj.sourceforge.net/) but not quite. The functionality I'm looking for is something I can throw into cron to run daily or weekly, scan a network(s), store the ...
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754 views

iptables & nmap on ubuntu

The following are my iptable rules on a ubuntu cloud server: cat /etc/iptables.rules: *filter :INPUT DROP [598:41912] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [456:35354] -A INPUT -i lo -j ...
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96 views

How to scan for which ports would be open to another location

I'm just assessing the security of my home server in preparation for opening it up to the internet. I've used nmap from a machine on my local network but I have firewall rules allowing access from the ...