Tente usar o nmap com um tempo muito frouxo, algo como
nmap -T1 -O 192.168.0.0/24
onde assumi que seu domínio de transmissão é 192.168.0.0/24 , se não os pls mudam de acordo.
O manual do nmap afirma:
-T paranoid|sneaky|polite|normal|aggressive|insane (Set a timing template) .
While the fine-grained timing controls discussed in the previous section are powerful and effective, some people find them confusing. Moreover, choosing the appropriate values can sometimes take more time than the scan you are trying to optimize. So Nmap offers a simpler approach, with six timing templates. You can specify them with the -T option and their number (0-5) or their name. The template names are paranoid (0), sneaky (1), polite (2), normal (3), aggressive (4), and insane (5). The first two are for IDS evasion. Polite mode slows down the scan to use less bandwidth and target machine resources. Normal mode is the default and so -T3 does nothing. Aggressive mode speeds scans up by making the assumption that you are on a reasonably fast and reliable network. Finally insane mode. assumes that you are on an extraordinarily fast network or are willing to sacrifice some accuracy for speed.
onde adicionei um negrito para enfatizar o motivo da escolha -T1 .
Além disso,
-O (Enable OS detection) .
Enables OS detection, as discussed above. Alternatively, you can use -A to enable OS detection along with other things.
Se você decidir ir por esse caminho, pegue um pacote de seis, você terá tempo suficiente para beber tudo antes que a tarefa acima seja concluída.