Linux port viewing command

1. Telnet command

(1) smooth ports

[Root @ portal_a/] # telnet 10.4.200.114 8500

Trying 10.4.200.114...

Connected to 10.4.200.114 (10.4.200.114 ).

Escape Character is '^]'.

(2) Port failure

[Root @ portal_a/] # telnet 10.4.200.114 9028

Trying 10.4.200.114...

 

 

2. NMAP command

---- Determine whether the machine port is open. View state

--------- Filtered: (filtered): it means that the firewall, filter, or other network barriers prevent the port from being accessed.

--------- Open (open)

--------- Closed (disabled)

(1) smooth ports

[Root @ portal_a/] # NMAP 10.4.200.114-P 8500

Interesting ports on 10.4.200.114:

Port State Service

8500/tcp open unknown

(2) Port failure

[Root @ portal_a/] # NMAP 10.4.200.114-P 9028

Interesting ports on 10.4.200.114:

Port State Service

9028/tcp filtered unknown

 

 

3. tracert command

(1) smooth ports

[Root @ portal_a/] # tracert 10.4.200.114 8500

Traceroute to 10.4.200.114 (10.4.200.114), 30 hops Max, 8500 byte packets

1 (10.4.203.227) 4.975 MS 5.060 MS 4.944 MS

2 (10.4.127.217) 5.562 MS 7.838 MS 3.946 MS

3 ** (10.4.200.129) 13.216 MS

4 (10.4.200.134) 4.305 MS 3.880 MS 3.544 MS

5 (10.4.200.htm) 15.213 MS 15.208 MS 15.163 MS

6 (10.4.200.114) 7.880 MS 5.613 MS 6.595 MS

(2) Port failure

[Root @ portal_a/] # tracert 10.4.200.114 9028

Traceroute to 10.4.200.114 (10.4.200.114), 30 hops Max, 9028 byte packets

1 ***

2 (10.4.127.217) 3.714 MS 6.855 MS 4.844 MS

3 ** (10.4.200.129) 11.719 MS

4 (10.4.200.134) 4.374 MS 3.874 MS 4.581 MS

5 (10.4.200.htm) 12.333 MS 12.309 MS 12.303 MS

6 ***

7 ***

8 ***

9 ***