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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nmap find all alive hostnames and IPs in LAN

How can I issue a nmap command that shows me all the alive machines' IP addresses and corresponding hostname s in the LAN that I am connected? (if this can be done in another way/tool you surely are ...
20
votes
1answer
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NMAP: Check if port 80 and 8080 is open

In our company, I want to check if users are running web servers on port 80 and 8080. I downloaded nmap and ran this command: nmap -p 80,8080 192.168.1.0-255 I got a list of IPs and tried to ...
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vote
5answers
18k 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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1answer
8k 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 ...
0
votes
2answers
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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 ...
0
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2answers
438 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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428 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 ...