Using Add rule in windows firewall, I was able to open TCP port 15537. When i am trying to executing command netstat -ano on terminal windows, this port is not listed. I tried to execute telnet command on terminal window (e.g. telnet IP port) but getting
Connecting To localhost...Could not open connection to the host, on port 15537: Connect failed
Then I downloaded PortQry application and execute it from different machine, this machine is also in the same network, the result I received was
"Not Listening".
I already spent more than 2 days and asked internal group but could not find solution.
Note: both machines are having Windows 10 OS.
No solution is needed as no problem is indicated in the question. You have opened a TCP port successfully. You have not made any attempt to cause anything to listen to that TCP port.
It's not clear what results you expected, but you got the results that you should have expected. Nothing is wrong. The port is open because you opened it. Nothing is listening on that port because you didn't set anything to listen on that port.
There may be some forwarding rules? Since the purpose of access is not on the local machine, the netstat command cannot see the port on listening, but it can see the next action based on this port, usually to do some forwarding
I am not very familiar with windows firewall configuration, but I know that if there is a forwarding rule in linux, like
-p tcp -m tcp --dport 8080 -j {other forwading chain}
we can not see 8080 listening on this host (netstat -tunpl), but telnet host:8080 may see connected
Use nmap instead of netstat for detecting opening port
nmap -p your_port_number your_local_ip
Run service on that port
For eg- In my case,in order to open port,I use
"service ssh start" or "service apache2 start "and it's open port 22 and 80 for connection respectively in my linux machine.
On using nmap in my lan network both ports opened.
Hope it help
Related
les
I created the instance from boot image.
but always can not open port 7000 via firewall rules...and egress is (allow all), anybody knows where the problem is?
System: Debian 10
ssh in terminal and
sudo natstat -plnt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 458/sshd
tcp6 0 0 :::22 :::* LISTEN 458/sshd
Is there any way to turn the port 7000 on ?
Encoutered the same issue when tring to open other ports like 5678...etc.
First of all you need to set the GCP firewall rule as "ingress".
Ingress is needed to allow incoming connections to the instance.
Regarding the ports, it does not open or activate by itself or in automatic, you need to have a service listening on that port.
However there are some tools used which allows you to activate the port by some time for testing purposes.
You can use tools like iperf3 to activate the port.
Install iperf3 for your vm with the command below.
sudo apt-get install iperf3
Once you have installed iperf3 you need to run the command below. ("-s" indicates your instance is in "server" mode, the "-p" is to set the port you prefer)
iperf -s -p 7000
On your remote machine (Client) you also need to install iperf3, if it is also a linux machine you can try the same command I mentioned earlier.
Once you have installed iperf3 use the below comamnd to reach the VM pointing the port 7000. ("-c" indicates client mode,the "-p" is to set the port the server is listening).
iperf -c [server ip address] -p 7000
Please refer to iperf
Another useful tool is netcat
I am building simple webpage.
I could run on my local host.
I made ec2 instance, I opened ports 22, 8000.
I could connect with ssh and run server for webpage,
but I get this error
this is my github address that contain the code.
enter link description herehttps://github.com/MoreNiceJay/django2
In your security group rules, open port 80
This is the standard port for http traffic
Other things to check: login to the host with ssh and use netstat |grep LISTEN to see if there is a process listening on port 80
We have to use port 80 for our server. But when I was trying to use it in Mac, it always said that the 80 is used, but I don't know which program uses it.
I searched it in Google, and someone said it's about apache, but I tried, which is not working. I found this: https://gist.github.com/kujohn/7209628 , but seems it's not working visiting our server by IP address.
I really don't know what's going on and how can I find out which program using port 80 and stop it.
Many thanks if anyone can help, I'm new using Mac. Thanks.
To find out what process is using port 80
go to Applications
open utilities.
open Activity Monitor.
click on the Memory tab,
look at the ports and the processes using them. Find port 80 and select it
go to the view on the menu bar and choose Quit process.
This will just kill the process, it will not stop a server instance that is already running from continuing to run.
(Correction: the Ports column shows the number of open ports (and files?), not the port number)
It is not clear if you are using a database management system or not and which one but one method that has worked for me using MAMP is as follows.
stop the server by using sudo apachectl stop command.
then change the port to port 80.
then restart your servers.
type the following in Terminal
sudo lsof -i -n -P | grep TCP
you will get a list - e.g. dropbox listens on 80
you can copy the output to a text editor, etc to search
On Mac ports below 1024 can only be bound by the root user.
Try launching your server as root user (with sudo), or try to use a port above 1024.
You can also try to add root permissions to your user in /etc/sudoers
# root and users in group wheel can run anything on any machine as any user
root ALL = (ALL) ALL
%admin ALL = (ALL) ALL
your_user_here ALL = (ALL) ALL
I was having this issue, apache was disabled via launchctl, but was still tying up port 80 after launch, I could start up apache and it would work, but after unloading it, I couldn't start up anything on port 80. I was using the built in web server for Python as an easy test. It would work on port 81, but not on port 80.
sudo python -m SimpleHTTPServer 80 -- wouldn't work
sudo python -m SimpleHTTPServer 81 -- would work
Here are the symptoms:
$ launchctl unload -w /System/Library/LaunchDaemons/org.apache.httpd.plist
/System/Library/LaunchDaemons/org.apache.httpd.plist: Could not find specified service
$ sudo lsof -i ':80'
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
Python 3353 root 3u IPv4 0xe455777a82799f05 0t0 TCP *:http (LISTEN)
The fix for me (after way too much searching) was simple:
sudo pfctl -F all
This flushed the packet filter, releasing port 80 (and others I assume 8080, 443, whatever ports apache might be tying up)
After that, and relaunching the python server, it came right up.
Might be Skype that is using port 80. If you have Skype installed and running try to change to a different port in the settings.
Port numbers in the range from 0 to 1023 are classified as 'well-known' and port number 80 is reserved for HTTP. Typically you have servers listening on port 80 to handle HTTP requests.
Source:
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
I have my Single node Hadoop installed on Google Compute Engine instance and i want to open port 50070 on that machine to access the hadoop dashboard. i configured in the firewall rule as tcp:50070 in compute engine networks. but still i am unable to access my port outside the network (ie . via internet). I tried nmap for the public ip of my GCE instance and i got a result which has only ssh port got opened all other ports are filtered .
Note: i am using debian 7.5 image
Make sure your daemon is listening on port 50070. If you have more than one networks in you project make sure the port is opened on the right network. You can run the following commands to check the information about your instance and network.
lsof -i
gcutil --project= getinstance
gcutil --project= listnetworks
gcutil --project= listfirewalls
gcutil --project= getfirewall
Check if IP/Port is allowed in iptables or not.
iptables -L
would show you all the records.
To allow port in iptables you can do the following:
sudo iptables -A INPUT -p tcp -m tcp --dport 50070 -j ACCEPT
sudo iptables-save -c
Short answer
In addition to configure the firewall rule at GCE web console make sure that your server is listening at 0.0.0.0 instead of 127.0.0.1
Long answer
In the context of servers, 0.0.0.0 means all IPv4 addresses on the local machine. If a host has two IP addresses, 192.168.1.1 and 10.1.2.1, and a server running on the host listens on 0.0.0.0, it will be reachable at both of those IPs - Source
In contrast 127.0.0.1 is the IP address used to stablish a connection to the same machine used by the user this address is usually referred as the localhost.
It's often used when you want a network-capable application to only serve clients on the same host. A process that is listening on 127.0.0.1 for connections will only receive local connections on that socket. - Source
Hence, if you try to stablish a connection to your server from internet and your server is listening at 127.0.0.1 at your GCE machine, then, from the server point of view a request has never been received and as a consequence Goocle Cloud Firewall will refuse the connection because there is no server listening at the opened port (in your case 50070).
I hope this answer helps to solve your problem. Best regards.
My lab runs RStudio on a server. A couple weeks ago, from my cousin's house, I successfully ssh'd into the server and pulled up the server-side RStudio through my local Firefox browser. Now when I try to access the server RStudio from home (via my own router), it doesn't work. I need help troubleshooting, and I'm guessing it's some problem on the router. I'm running Mac OSX 10.6.8. No idea what the university server's running, but I don't think it's a server-side problem.
Here's how it worked the first time I did it, at my cousin's house: first, I VPN into the university network; then I call SSH with port forwarding; then I open a Firefox browser, connect to my localhost port, and it opens up RStudio on the server side which I can access through my local browser window.
Here's the problem I'm having right now when I try to log-in from my home network:
I can make the VPN connection successfully. I can also set up SSH successfully with this command:
ssh -v -L 8783:localhost:8783 myacct#server.com
Here are the last several lines of the verbose output from the successful ssh command:
debug1: Authentication succeeded (password).
debug1: Local connections to LOCALHOST:8783 forwarded to remote address localhost:8783
debug1: Local forwarding listening on 127.0.0.1 port 8783.
debug1: channel 0: new [port listener]
debug1: Local forwarding listening on ::1 port 8783.
debug1: channel 1: new [port listener]
debug1: channel 2: new [client-session]
debug1: Entering interactive session.
Last login: Mon Sep 2 04:02:40 2013 from vpnipaddress
So I think I'm still succeeding at the VPN and SSH stage (though I don't know why it says my last login was Sep 2 when I've logged in a few times since then).
Next, I open Firefox, and I type localhost:8783, and instead of getting an RStudio server app through my browser window, I get the following errors:
In the Firefox browser window, it says: Server not found, Firefox can't find the server at www.localhost.com, Check the address for typing errors etc.
In the terminal window, it says:
debug1: Connection to port 8783 forwarding to localhost port 8783 requested.
debug1: channel 3: new [direct-tcpip]
channel 3: open failed: connect failed: Connection refused
debug1: channel 3: free: direct-tcpip: listening port 8783 for localhost port 8783, connect from 127.0.0.1 port 50420, nchannels 4
I'm not sure what I've got wrong. I haven't changed anything on my laptop since my last successful connection. I'm on my own router (instead of my cousin's), so maybe I need to mess with the firewall? I already allowed ports 22 and 8783 to come through the firewall to my laptop (I'm not even sure I needed to do that though). Help?
ssh -v -L 8783:localhost:8783 myacct#server.com
...
channel 3: open failed: connect failed: Connection refused
When you connect to port 8783 on your local system, that connection is tunneled through your ssh link to the ssh server on server.com. From there, the ssh server makes TCP connection to localhost port 8783 and relays data between the tunneled connection and the connection to target of the tunnel.
The "connection refused" error is coming from the ssh server on server.com when it tries to make the TCP connection to the target of the tunnel. "Connection refused" means that a connection attempt was rejected. The simplest explanation for the rejection is that, on server.com, there's nothing listening for connections on localhost port 8783. In other words, the server software that you were trying to tunnel to isn't running, or else it is running but it's not listening on that port.
Posting this to help someone.
Symptom:
channel 2: open failed: connect failed: Connection refused
debug1: channel 2: free: direct-tcpip:
listening port 8890 for 169.254.76.1 port 8890,
connect from ::1 port 52337 to ::1 port 8890, nchannels 8
My scenario; i had to use the remote server as a bastion host to connect elsewhere. Final Destination/Target: 169.254.76.1, port 8890. Through intermediary server with public ip: ec2-54-162-180-7.compute-1.amazonaws.com
SSH local port forwarding command:
ssh -i ~/keys/dev.tst -vnNT -L :8890:169.254.76.1:8890
glue#ec2-54-162-180-7.compute-1.amazonaws.com
What the problem was:
There was no service bound on port 8890 in the target host. i had forgotten to start the service.
How did i trouble shoot:
SSH into bastion host and then do curl.
Hope this helps.
Note: localhost is the hostname for an address using the local (loopback) network interface, and 127.0.0.1 is its IP in the IPv4 network standard (it's ::1 in IPv6). 0.0.0.0 is the IPv4 standard "current network" IP address.
I experienced this error with a Docker setup. I had a Docker container running on an external server, and I'd (correctly) mapped its ports out as 127.0.0.1:9232:9232. By port-forwarding ssh remote -L 9232:127.0.0.1:9232, I'd expected to be able to communicate with the remote server's port 9232 as if it were my own local port.
It turned out that the Docker container was internally running its process on 127.0.0.1:9232 rather than 0.0.0.0:9232, and so even though I'd specified the container's port-mappings correctly, they weren't on the correct interface for being mapped out.
In my case, it worked after running the vncserver on linux.
Entered this on linux command line : sudo ssh -L 5901:localhost:5901 -i <ssh_private_key> <username>#<public-IP-address>
Type there vncserver
Go to VncViewer application and connect using localhost:5901
I used to meet the similar problem because 'localhost' was not available on server when it restarted network service, e.g. 'ifdown -a' but followed by only 'ifup -eo1'. Besides server is not listening to the port, you can also check 'localhost' is available or not.
ps: Post it just hope someone who has the similar problem may benefit.
I had this problem when I wanted to make a vnc connection via a tunnel.
But the vncserver was not running.
I solved it by opening the channel on the remote machine with vncserver :3.
In my case, it worked after checking the correct IP address of the user credentials
previously I was using the wrong IP of the server
ssh -NfL 127.0.0.1:8084:127.0.0.1:8888 user#ip_address_of_server
after correcting it, works fine.
Encountered with the same error.
In my case, I found the problem was in the config file of jupyter.
Let's say there are 3 computers named A, B, and C, and A can access B but can't access C; B can access C.
To access jupyter-notebook service of C from A, first I established ssh tunnel from A to C through B, then I access jupyter-notebook by typing localhost:port_number, then I got the error.
Finally the problem was solved by writing the "c.NotebookApp.ip = '0.0.0.0'" in jupyter-notebook's config file, where '0.0.0.0' allows the access of other IPs.
Hope someone in a similar situation may benefit.
I had the same error when I was trying to tunnel my mlflow ui over ssh to view remotely. As mentioned in the first answer, the error arises because nothing on the server is listening for the port. This, for me, is because I forgot to start the mlflow app on my remote machine! So in general – make sure the app you're trying to access remotely is running.
Just replace localhost with 127.0.0.1.
(The answer is based on answers of other people on this page.)
This means the remote vm is not listening to current port i solved this by adding the port in the vm server