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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Why does nmap send two packets in order to test a single port

I run nmap with root privileges using sudo so I assume it has full access to creat raw sockets. Wireshark shows two packets used to test a single port when I used the command sudo nmap ...
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1answer
36 views

nmap unable to split netmask from target expression [closed]

I'm trying to scan my website with nmap to see what is visible from outside...but nmap returns this value... Starting Nmap 6.47 ( http://nmap.org ) at 2015-05-06 01:06 PDT Unable to split netmask ...
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1answer
51 views

How to test iptables settings by port scanning?

I want to test my iptables and prove that it only allows traffic for given Protocol / Port - combinations. How I can use as a target for a port scan?
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1answer
83 views

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 ...
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1answer
45 views

Why is port 443 (but not port 80) being exposed to nmap when iptables is configured to drop the traffic?

A Debian box is running web services on ports 80 and 443 and iptables is configured to allow web traffic only from white listed ip addresses. A second Debian box (that is not white listed) is using ...
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47 views

Unknown device showing up in network scan

I need some help finding a device that has been showing up whenever I scan my network using Spiceworks' "Inventory" scan. I can ping the device, but nslookup returns a non-existent domain, and ...
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0answers
31 views

Find any/first alive host in subnet

I'm trying to find a quick way to check if there are ANY alive hosts in an IP range by pinging them. eg: i don't need to know what hosts are alive, just if one or more is responding to a ping. This ...
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0answers
28 views

One device shows down when more than 160 ip addresses are scanned with nmap

This is bugging me. I consistently have a single device that fails to respond to an nmap scan when more than ~160 IP addresses are specified. I seem to get mixed results between 150-160 IP addresses ...
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23 views

outlook doing remote portscanning

A while ago I switched my mailbox on another domain and configured outlook with an exchange server on that domain. Recently for some strange reason my hosting provider has been complaining that ...
0
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1answer
85 views

ACL Rule to Open UDP Ports

I have the current rules in an attempt to open port 5060 and 10000-20000 for my VoIP provider. We are on a Cisco 1921 router. This ACL is applied to the WAN port on the router facing the ISP. Nmap ...
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4answers
1k views

Is there a way to see what is actually filtering TCP port communication?

nmap -p 7000-7020 10.1.1.1 Will output all the filtered ports Starting Nmap 6.40 ( http://nmap.org ) at 2015-03-04 12:18 EET Nmap scan report for 10.1.1.1 Host is up (0.00091s latency). PORT ...
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1answer
131 views

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 ...
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2answers
135 views

Generate List of IP's With User Names On Windows Network

We recently setup GFI WebMonitor on our network which is giving me back IP's instead of User's. I'm in the process of determining whether we will be able to implement authentication on the proxy to ...
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2answers
110 views

nmap results to find open ports for SIP

I suspect that a firewall, or other security, on either the router, or on tleilax or doge is causing a problem with SIP calls. How do I establish that the connection is allowed and not being blocked? ...
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1answer
156 views

How to reverse arp using nping for Windows

I would like to send a reverse ARP to resolve an IP address given a MAC address using nping for Windows. The documentation is not clear on how this should work and I'm unable to find any examples ...
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1answer
127 views

Port suddenly closed. How to re-open?

I've written a software module in PHP that manages the saving of data in different data stores (MySQL, ElasticSearch and Redis). To test the module, I've created several test plans in Apache JMeter, ...
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2answers
165 views

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 ...
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1answer
239 views

Can a port be in the listen state and be closed?

Servers running Debian7.7, Mongodb 1.2.0.6-1.1, Nmap6.0 - Thanks for your time. I've user who can't connect to mongodb from his Win7 desktop. He has mongodb installed on it and he's trying to connect ...
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2answers
160 views

nmap port 3128 shows open but no squid running

Im trying to lock down an Ubuntu server and ran nmap -T4 against my server. Everything looks right except that it shows port 3128 open but I dont run a squid server or anything else I know of on that ...
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1answer
76 views

nmap: why is it scanning port 80 with TCP ACK and not SYN?

While reading nmap man pages, I read for the -sn option: The default host discovery done with -sn consists of an ICMP echo request, TCP SYN to port 443, TCP ACK to port 80, and an ICMP timestamp ...
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1answer
31 views

I have a IP address with some open services. How could I contact the owner? [closed]

After having serious problems (DNS incident) I found out an IP address of a machine. Is it in any way possible to contact the owner without knowing anything else like email, domain name or website? I ...
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1answer
148 views

HTTP Ports are Filtered on New Virtual IPs in LVS (Linux Virtual Server) Load Balancer

I inherited a Linux Virutal Server (LVS) load balancer on CentOS 5.10. Its been running with no issues for quite some time with no worries. Now when I add a new virutal IP (VIP), all HTTP traffic ...
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1answer
93 views

nmap repeats the scan to a specific port multiple time

I scanned a subnet (16 hosts) while dumping the network traffic with wireshark. I did it 2 times and I noticed that in the traffic there is the normal SYN-SYN/ACK and SYN-RST from open/closed port, ...
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2answers
47 views

How best to enumerate a server network

What techniques do you typically use, when you start a gig at a complex environment and no one can tell you what servers are out there, and documentation doesn't exist? I typically start off with ...
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1answer
261 views

ports I open with iptables appear closed [closed]

I opened the following ports with iptables on Debian 7: iptables -X iptables -F iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT iptables -A INPUT -m state --state ...
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1answer
98 views

NMAP service probe or normal port scan [closed]

Apologies - I am very new to these things.I read that nmap-service-probes will display the service that the port is using while nmap -sS will send a stealth SYN which is also capable of ...
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2answers
128 views

How do I test my firewall rules?

I've setup some rules in ufw and I've turned it on. Now I want to ensure my rules actually block traffic. However, when running nmap -PN -p <my_port> <ip> from my local workstation it ...
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1answer
4k views

Two Identical mac addresses on the same lan - Tracking one down?

So I've been playing around with nmap, and found a curious problem, two devices in the same subnet have the same mac address. I would like to track down the second mac, as the first one is the sonic ...
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2answers
345 views

Nmap: find free IPs from the range

Is there a way to scan for free IPs on the network? I use nmap -sP 192.168.1.0/24 but this actually shows hosts that are up.
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2answers
42 views

Can zenmap disrupt my server? [closed]

Title says almost everything already. I'm trying to increase the security on our servers but I need verification that the Information Gathering tool ZenMap or NMap does not disrupt our servers. The ...
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1answer
694 views

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 ...
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1answer
246 views

nmap lists host as up despite being black listed

I have an iptables rule setup that marks addresses as suspicious if they connect on certain ports or any unopen ports. If more than three consecutive connections are made without authentication, then ...
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1answer
257 views

Trace /8 address space with nmap

I'm trying to sketch out a network topology map using the following command nmap -sP -PE -PS22,25,80 -PA21,23,80,3389 -PU -PO -oX topology.xml --traceroute 10.0.0.0/8 (10.0.0.0/8 because no one ...
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1answer
1k views

Detect if remote host is running Windows or Samba

From a Linux server, how can I quickly determine if a remote machine is running Windows or Samba? I want to run commands on remote Windows machines (XP and 7) to list the installed software and ...
0
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1answer
72 views

nmap shows services I'm unaware of

When I run nmap <host> on my server it says the following ports are open, but my iptables have no rules explicitly allowing them. 135/tcp filtered msrpc 139/tcp filtered netbios-ssn 445/tcp ...
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1answer
75 views

Finding ips and hosts in a LAN . Different results

I need to scan a LAN and match hosts with ips. I used nmap -sL 192.168.1.* and i got a list of hosts and ips as i wanted. But when i checked using ipconfig on a few machines i saw that resuts form ...
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votes
2answers
1k views

Ports do not open after rules appended in iptables [closed]

I have a server that I am trying to setup for OpenVPN. I have followed all the steps, but I see that when I try to connect to it in Windows, it doesn't allow me, it just hangs on connecting, so I did ...
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0answers
156 views

Why does scanlogd miss port scans?

I am running scanlogd to detect port scans. I have observed the following to generate a log message in /var/log/syslog. When I use zenmap (nmap gui) to port scan this system from another computer on ...
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4answers
2k views

Ping only OS Detection with nmap?

I am interested in using nmap for discovery, and to figure out the OS of each host. I understand that nmap does this, and can be enabled and controlled as described in the man page: OS detection ...
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votes
2answers
250 views

Nmap scans the host but cannot ping the host [closed]

My laptop is connected to a network where we have routers with filters. I can use nmap to scan alive hosts and I can see open ports (mostly port 80). But then, when I try to ping those hosts, I dont ...
0
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2answers
53 views

making sense of the nmap options

An nmap option I see in some examples uses the -sP option, but I haven't seen this listed anywhere in their options or --help. Is -sP an option you construct from the other options? If so, please ...
0
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1answer
128 views

Do an os scan with nmap only

Is it possible to do an OS detection scan with nmap without scanning a port? I really need only OS detection and try to reduce the amount of traffic as much as possible. By the way what is the most ...
4
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1answer
511 views

command for MAC broadcast

I am looking for a command to discover all hosts on the same LAN segment from a host with unassigned IP, default gateway, and subnet. I know there's ping 255.255.255.255 but that operates at layer 3 ...
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1answer
172 views

psad does not detect nmap [closed]

I am new to this and just installed psad. I ran nmap several times on a server but psad didn't log this psad --Status. I configured it like this: ...
0
votes
1answer
115 views

NAT and find inside global address

To try to find the inside local address of a host, on a LAN with 1 Cisco wireless router, I run nping on one Windows7 host 192.168.1.138. C:\>nping --ec "public" -c 1 echo.nmap.org SENT ...
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2answers
302 views

ping and identify Cisco model without physical access or login?

There are several Cisco devices on my network which I can find with ping or nmap but I have no idea what the type (e.g. switches, routers) or specific model is. Is there some way to find this out ...
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1answer
848 views

Need equivalent of command with nmap, awk and grep for Windows machines with PowerShell and/or Perl

Please see this thread for reference How can I scan using nmap and Zenmap all hostnames that begin with a particular string? One of the answers in the thread above uses the following query (I take ...
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2answers
229 views

How can I scan using nmap and Zenmap all hostnames that begin with a particular string?

I have a number of nodes on a couple of networks whose hostnames all start with org. Some examples are: orgwebsvr1 orgwebsvr2 orgwebsvr3 orgdbsvrmysql orgdbsvrmssql orgdbsvrosql With nmap, I know ...
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1answer
1k views

Port 443 is open but IP tables denies it

When I run the following command on my Ubuntu instance: $ nmap host I see that port 443 is open: Starting Nmap 5.21 ( http://nmap.org ) at 2013-03-19 05:36 PDT Nmap scan report for [host redacted] ...
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1answer
165 views

Windows AdvFirewall and nmap scans

I come from a Unix background but got the task of configuring a Windows firewall on a public facing server. I find awkward that any nmap scan I perform against the public IP reports all TCP ports ...