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Resolved How can I find open ports on a remote computer

Discussion in 'Networking (Hardware & Software)' started by zhshqzyc, 2013/11/25.

  1. 2013/11/25
    zhshqzyc

    zhshqzyc Inactive Thread Starter

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    I have a port for the production of an application.
    Code:
    string sIpaddress = @ "gtcp://" + ips[0].ToString() +  ":54331 ";
    The port is 54331.

    Now I want to debug with a different port, but I don't know what can I use.
    I want to list all open ports for the remote machine.
     
    zhshqzyc,
    #1
  2. 2013/11/25
    PeteC

    PeteC SuperGeek Staff

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    Moved to Networking
     
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  4. 2013/11/25
    retiredlearner

    retiredlearner SuperGeek WindowsBBS Team Member

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  5. 2013/11/25
    zhshqzyc

    zhshqzyc Inactive Thread Starter

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    It seems that there is no such command "portqry" in windows 7.
     
    zhshqzyc,
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  6. 2013/11/26
    retiredlearner

    retiredlearner SuperGeek WindowsBBS Team Member

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  7. 2013/11/26
    Arie

    Arie Administrator Administrator Staff

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    The article Neil linked to says at the top:

     
    Arie,
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  8. 2013/11/27
    zhshqzyc

    zhshqzyc Inactive Thread Starter

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    Code:
    c:\PortQryV2>PortQry.exe -n 11.50.96.228 -r 80:65535

Querying target system called:

 11.50.96.228

Attempting to resolve IP address to a name...


IP address resolved to cfemsg01.corporate.my.com

querying...

TCP port 80 (http service): LISTENING

Error opening socket: 10051


Network unreachable.

c:\PortQryV2>
    Why?
     
    zhshqzyc,
    #7
  9. 2013/11/27
    SpywareDr

    SpywareDr SuperGeek WindowsBBS Team Member

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  10. 2013/11/27
    zhshqzyc

    zhshqzyc Inactive Thread Starter

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    No, it is an internal ip address. I faked it just as an example.
     
    zhshqzyc,
    #9
  11. 2013/11/27
    SpywareDr

    SpywareDr SuperGeek WindowsBBS Team Member

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    Looks like blocked ports somewhere.
     
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  12. 2013/11/27
    zhshqzyc

    zhshqzyc Inactive Thread Starter

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    Well even I limit a small range say
    Code:
    c:\PortQryV2>PortQry.exe -n 11.50.96.228 -r 80:81
    It is still wrong.
    If I remove -r part.
    Code:
    c:\PortQryV2>PortQry.exe -n 11.50.96.228
    Then
    Code:
    querying...

TCP port 80 (http service): LISTENING
     
    zhshqzyc,
    #11
  13. 2013/11/27
    SpywareDr

    SpywareDr SuperGeek WindowsBBS Team Member

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    The easiest way to test and see whether a port is open on a remote computer can be accomplished by accessing the computer with the remote desktop wizard and then looking at its firewall settings with the netstat command.
    1. Click Start, type "Remote Desktop Connection" (sans the quotes) into the Search box and press [Enter]

    2. Input the IP address of the remote computer and press "Connect ".

    3. If prompted, enter a username and password.

    4. On the remote computer, click "Start," type "cmd" in the "Search" box and press [Enter].

    5. Type the command:

      netstat -an |find /i "listening "​

      press [Enter] and you should see a list of open ports on the remote computer.
     
    SpywareDr,
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  14. 2013/11/27
    TonyT

    TonyT SuperGeek Staff

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    Socket error 10051 ALWAYS means: computer is unreachable. This can be caused by: misconfigured router, router down, hardware firewall rules or software firewall rules.

    Since you know the router is working fine, the error is the result of a firewall rule.

    That error will get spit out as soon as you query a port that is not in use, especially when scanning a range such as:
    PortQry.exe -n 11.50.96.228 -r 80:65535

    The error will get returned if port 81 is not in use or if a firewall rule is blocking connections to port 81 (or a service or program that uses port 81).

    If you just do:
    PortQry.exe -n 11.50.96.228
    it will return:
    querying...
    TCP port 80 (http service): LISTENING
    because PortQry queries port 80 by default.

    To really determine the status (open, closed, filtered) of ports on a remote system use nmap. They do have a Windows version. Most all firewalls cannot thwart the specialized queries that nmap can do. Example, 2 different port scans of google return 2 different sets of results:

    Code:
    tonyt@d830:~$ [B]sudo nmap -v google.com[/B]

Starting Nmap 5.00 ( [url]http://nmap.org[/url] ) at 2013-11-27 18:30 EST
NSE: Loaded 0 scripts for scanning.
Warning: Hostname google.com resolves to 11 IPs. Using 74.125.228.103.
Initiating Ping Scan at 18:30
Scanning 74.125.228.103 [4 ports]
Completed Ping Scan at 18:30, 0.07s elapsed (1 total hosts)
Initiating Parallel DNS resolution of 1 host. at 18:30
Completed Parallel DNS resolution of 1 host. at 18:30, 0.04s elapsed
Initiating SYN Stealth Scan at 18:30
Scanning iad23s08-in-f7.1e100.net (74.125.228.103) [1000 ports]
Discovered open port 443/tcp on 74.125.228.103
Discovered open port 80/tcp on 74.125.228.103
Completed SYN Stealth Scan at 18:30, 16.11s elapsed (1000 total ports)
Host iad23s08-in-f7.1e100.net (74.125.228.103) is up (0.10s latency).
Interesting ports on iad23s08-in-f7.1e100.net (74.125.228.103):
Not shown: 998 filtered ports
PORT    STATE SERVICE
80/tcp  open  http
443/tcp open  https

Read data files from: /usr/share/nmap
Nmap done: 1 IP address (1 host up) scanned in 16.39 seconds
           Raw packets sent: 2012 (88.504KB) | Rcvd: 13 (556B)



tonyt@d830:~$ [B]sudo nmap -v PN google.com[/B]

Starting Nmap 5.00 ( [url]http://nmap.org[/url] ) at 2013-11-27 18:30 EST
NSE: Loaded 0 scripts for scanning.
Warning: Hostname google.com resolves to 11 IPs. Using 74.125.228.103.
Initiating Ping Scan at 18:30
Scanning 2 hosts [4 ports/host]
Completed Ping Scan at 18:30, 0.14s elapsed (2 total hosts)
Initiating Parallel DNS resolution of 2 hosts. at 18:30
Completed Parallel DNS resolution of 2 hosts. at 18:30, 0.04s elapsed
Initiating SYN Stealth Scan at 18:30
Scanning 2 hosts [1000 ports/host]
Discovered open port 22/tcp on 80.68.93.100
Discovered open port 53/tcp on 80.68.93.100
Discovered open port 587/tcp on 80.68.93.100
Discovered open port 110/tcp on 80.68.93.100
Discovered open port 21/tcp on 80.68.93.100
Discovered open port 995/tcp on 80.68.93.100
Discovered open port 80/tcp on 80.68.93.100
Discovered open port 443/tcp on 74.125.228.103
Discovered open port 80/tcp on 74.125.228.103
Increasing send delay for 80.68.93.100 from 0 to 5 due to 29 out of 96 dropped probes since last increase.
Completed SYN Stealth Scan against 74.125.228.103 in 38.26s (1 host left)
Completed SYN Stealth Scan at 18:31, 39.87s elapsed (2000 total ports)
Host tedside.pitcairn.net.pn (80.68.93.100) is up (0.11s latency).
Interesting ports on tedside.pitcairn.net.pn (80.68.93.100):
Not shown: 989 closed ports
PORT    STATE    SERVICE
21/tcp  open     ftp
22/tcp  open     ssh
25/tcp  filtered smtp
53/tcp  open     domain
80/tcp  open     http
110/tcp open     pop3
135/tcp filtered msrpc
139/tcp filtered netbios-ssn
445/tcp filtered microsoft-ds
587/tcp open     submission
995/tcp open     pop3s

Host iad23s08-in-f7.1e100.net (74.125.228.103) is up (0.055s latency).
Interesting ports on iad23s08-in-f7.1e100.net (74.125.228.103):
Not shown: 998 filtered ports
PORT    STATE SERVICE
80/tcp  open  http
443/tcp open  https

Read data files from: /usr/share/nmap
Nmap done: 2 IP addresses (2 hosts up) scanned in 40.27 seconds
           Raw packets sent: 3190 (140.312KB) | Rcvd: 1057 (42.352KB)
     
    TonyT,
    #13

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