nmap find all alive hostnames and IPs in LAN

nmap versions lower than 5.30BETA1:

nmap -sP 192.168.1.*

newer nmap versions:

nmap -sn 192.168.1.*

This gives me hostnames along with IP adresses, and only pings the hosts to discover them. This will only give you the hostnames if you run it as root.

EDIT: As of Nmap 5.30BETA1 [2010-03-29] -sP has been replaced with -sn as the preferred way to do ping scans, while skipping port scanning, just like the comments indicate:

Previously the -PN and -sP options were recommended. This establishes a more regular syntax for some options that disable phases of a scan:

• -n no reverse DNS
• -Pn no host discovery
• -sn no port scan

nmap -sP 192.168.1.0/24

Note that name resolution is only as good as the reverse-dns population is. Also note that this won't get you systems which are firewalled against ping (which practically every windows workstation is by default).

If you are local to the systems (ie on the same subnet) you can do something like

for i in `seq 1 254` ; do arping -c 1 192.168.1.$i | grep reply ; done

...but weird things happen to me sometimes when I wrap arping up in a loop. Also you have to do the lookup yourself, with something like

dig +short -x $IP

You can scan an entire subnet, can use wildcards also.

nmap 192.168.8.*

or

nmap 192.168.8.1/24

NMAP will return the 'reverse-lookup' of the IP address in question, it can't return the forward lookup address. Or addresses in the case of Web Servers doing name-based virtual hosting. Nmap isn't the tool for this.

nmap -sP 192.168.0.0/24 will output something like :

> nmap -sP 192.168.0.0/24

Starting Nmap 4.00 ( http://www.insecure.org/nmap/ ) at 2010-06-22 22:27 CEST
Host 192.168.0.0 appears to be up.
Host 192.168.0.1 appears to be up.
Host abcd.domain.tld (192.168.0.2) appears to be up.
Host def.domain.tld (192.168.0.3) appears to be up.
Host fdsf.domain.tld (192.168.0.4) appears to be up.
Host reht.domain.tld (192.168.0.5) appears to be up.
Host vcxbfd.domain.tld (192.168.0.6) appears to be up.
Host ezqs.domain.tld (192.168.0.7) appears to be up.
Host 192.168.0.8 appears to be up.
Host ilolio.domain.tld (192.168.0.9) appears to be up.
Host ipbd.domain.tld (192.168.0.10) appears to be up.
Host cdekf.domain.tld (192.168.0.11) appears to be up.
Host 192.168.0.12 appears to be up.
Host 192.168.0.13 appears to be up.
Host 192.168.0.14 appears to be up.
Host 192.168.0.15 appears to be up.
Host ainv.domain.tld (192.168.0.16) appears to be up.
Host 192.168.0.17 appears to be up.
Host 192.168.0.18 appears to be up.
Host wzdkz.domain.tld (192.168.0.19) appears to be up.
[…]
Nmap finished: 256 IP addresses (256 hosts up) scanned in 7.491 seconds

You can use the following command :

nmap -v -A $IP

if this can be done in another way/tool you surely are welcome to answer

You can simply use arp command like this:

$ arp -a

Best and Fastest way to ping all Ips in Local Net is by disabling DNS reverse Resolution

Use :
NMAP -sn 192.168.1.1-255

this will scan all 255 hosts in IP range 192.168.1.1 - 192.168.1.255

If you want a easily parse-able file

Use :
NMAP -sn -oG Name.txt 192.168.1.1-255

Since there is no given IP for the LAN we could assume it is 192.168 but that's not always the case, so the first thing is to discover our IP address and our subnet mask.

use ifconfig for this and use regexp to clean the results

Now assuming your Ip is 192.168.0.100 and your mask is 255.255.255.0 then you can scan 1-254 like so

nmap -sn 192.168.0.1-254 
or 
nmap -sn 192.168.0.0/24

to see hostnames and MAC addresses also, then run this as root otherwise all the scans will run as a non-privileged user and all scans will have to do a TCP Connect (complete 3-way handshake) to get something. As root, you run Syn and don't have to finish the 3-way handshake.

This is basically what you need to answer your question and get what you wanted. There is a wealth of parameters but each serves a special purpose.

----edit

I've just noticed hostname. You can use a service discovery scan since it will execute several scripts(one of which is nbstat.nse) and will return hostnames. Don't expect to get the hostnames of all the machines that you scan.

nmap -sV target

or you can just run the specific nbstat.nse script and gain time and effort.

nmap -sU -p137 --script nbstat.nse target

nbstat.nse uses UDP port 137. In some cases you might also get the hostname from SNMP using the snmp-interfaces script but that will require UDP port 161 to be open.

nmap -sU -p161 --script snmp-interfaces.nse target

I think you should run this:

sudo nmap -sU --script nbstat.nse -p137 10.10.10.*