How do i discover open port on remote server, nmap cant see it?

postcd

Hello,

on my linux server is running SSH on port 3501

im ABLE to connect my remote linux server from my home PC using following command:

ssh -l root -p 3501 servIP

but when i do:

nmap servIP -p3490-3550 -Pn

or

nmap servIP -p3501 -Pn

or

nmap servIP -p3501

it find no port and more over says:

Starting Nmap 5.51 ( http://nmap.org ) at 2016-04-14 08:43 EDT

Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn

Nmap done: 1 IP address (0 hosts up) scanned in 0.49 seconds

The service like https://pentest-tools.com/network-vulnerability-scanning/tcp-port-scanner-online-nmap is able to find open SSH port.

I would like to be able to scan range of ports of my remote server and discover which are open. So which nmap command to use or which other linux tool to use for this?

Ishaq

Do you have ICMP filtered?

Ishaq

Try this:

nmap IP -p3490-3550 -d -d

postcd

Ishaq: no it not found any port. Ping (assuming icmp) works:

64 bytes from servIP: icmp_seq=1 ttl=55 time=94.0 ms

globalRegisters

If you have iptables rules on the target server, use the command below to see where the packets are going.

iptables -nvL

iptables -z (to reset counters)