I have setup a CentOS VM to test Hadoop. I set a network interface in NAT mode with a paravirtualized network type interface. Port redirection for SSH (TCP 22) works without issues. However some other ports do not seem to fully work (9870, 8042, 9864). I can see some "action" happening. Let me give an example for port 9870.
These are my rules (remember I said the SSH rule works without issues):
RulesX TCP 127.0.0.1 59870 10.0.3.15 9870
When I try to access http://127.0.0.1:59870 I get automatically redirected to https://127.0.0.1:59870 but eventually I get a ERR_TIMED_OUT error.
Tracing the traffic on the VM, I can see the traffic coming in but I cannot see any response back (I have one single network interface):
I am not sure what else to look at.
Any idea is highly welcome. Thank you!
More than likely, you need to open the non-standard ports on Centos firewall.
Open firewall port on CentOS 7
Related
Sorry for the basic question but im a complete noob on those matters.
I have a cloud server where i run a jup[yter notebook server, which normally is run on port 8888.
However when i try to connect to it from work, it doesnt work, which i suspect is due to the firewall.
I can connect from work to a regular ssh session through port 22 or 443.
However the jupyter notebook refuses to be run on those ports, probably because they are allocated already.
I tried to run PortQry to get the open ports on my work server (which is windows) and it reurned port 50248. I tried to have my jupyter server to listen on that one but it didnt work.
I also tried to scan the open port of my work server, but i received a warning from AWS! And the few ports that were returned as seemingly opened didnt work either when i set up my jupyter notebook to listen on them.
I would like to understand:
On my own server: How can i identify which port the jupyter server program can listen on?
On my work machine: How can i identify which one of my own server port would be let through the firewall of my work?
You need to use SSH local port forwarding.
https://help.ubuntu.com/community/SSH/OpenSSH/PortForwarding
You will open a SSH connection to your server but a local port, lets say 4444, will connect over the SSH connection and resolve to 8888 on the remote server.
With this you'd be able to open a browser locally and go to localhost:4444 and it would resolve to your remote hosted site. The command for this locally would be something like -
ssh -L 4444:localhost:8080 yourremoteserveraddress
An alternative option would be to use a SOCKS proxy via dynamic forwarding but this would involve needing to reconfigure your browser.
Always keep in mind any company policies around this type of thing. Even though 22 and 443 are open to the internet, use of them in this manner may break a policy and there is always the possibility of the company using a MITM proxy to monitor for this type of usage, specifically on 443.
I have setup a simple HTTP java server running locally on port 8000. It simply prints a message "Hello world" when a request comes. When I try to ping it from the browser by running http://localhost:8000/test I get my message printed.
I want to get the same results from another computer that is not local. When I try to use my public IP lets say http:/43.xxx.xxx.xxx:8000/test (even from the same machine) I get an ERR_CONNECTION_REFUSED .
I probably suspect that has something to do with the firewall. Can anyone guide me a little more because I lack the experience?
Thanks in advance
You don't specify what host OS your server/firewall is running so I'll keep this generic...
Without knowing your application, it seems like the server is sending a reset (RST packet) when the first SYN packet shows up indicating that the port (on that interface [your external]) is closed. You can do a quick port scan from here (https://mxtoolbox.com/PortScan.aspx) if you don't have access to a remote machine to test with. Odds are, TCP/8000 will not be open.
If it is, in fact, closed, you'll have to look at the firewall that your host OS is running and find out how to allow TCP/8000 to your host. In a major firewall vendor, your rule would look similar to this:
Source: Any
Destination: Your Public IP Address
Service: TCP/8000
Action: Allow
Logging: Full
That being said, you mentioned this was a PC so look into "iptables" (if you're running *nix) or the Windows Firewall (if you're running Windows) on adding firewall rules (Unfortunately I just joined and can't ask questions/comments, yet).
If you really want to find out what packet is being sent, run a tcpdump on your external interface (let's say eth1) (assuming your remote IP is 1.2.3.4 and your home public IP is 4.5.6.7):
tcpdump -nn -vvv -e -s 0 -X -c 100 -i eth1 host 1.2.3.4 and host
4.5.6.7 and port 8000
Here you're looking for the SYN/SYN-ACK/ACK for a successful TCP negotiation or SYN/RST if there is a firewall rejecting (not dropping) the TCP stream to the port.
Once the port is open on the host OS firewall, take a look at the application to make sure it's configured properly. If this were a standard webserver, you could take a look at the configuration files for the "Allow from" directives to make sure that everyone can access the site. If this is a custom application that you've created, you'll have to check this yourself.
I finally solved my problem. I needed to open a forwarding port in my router that maps my local ip address to the public. My router is TP Link so this what I did:
http://www.tp-link.com/us/faq-72.html
Also in order for this to work every time and not to have to reconfigure this every time I reconected to the router (because I get a new local IP), I have created a static local ip for my server following this guide:
http://www.tp-link.com/us/faq-182.html
Thanks for all the replies.
i am configuring voip server on centos 7 (google cloude) but some ports are blocked .
I disabled Firewall in centos
I added firewall rule to google networking.1
plz help m new to it.
You are doing it properly. Also, you can enable your Firewall in centos and just open the required ports.
To make sure that these ports are in fact open now and available to you, you should try running a small sample server on that port and try to access it from outside on that same port. If you can do so, then the networking part is done. Rest should be configured on your VOIP side.
I have configured jetty-maven-plugin in my eclipse Mars and I can run the server using jetty start and stop goals. I can able to access the website using http://localhost:8080/myapp but not using local IP address(i.e., http://192.168.0.5:8080/myapp) from my own computer or other computers connected in the same network via LAN and Wi-Fi.
As mentioned as a solution in these posts,
how to make jetty server accessible from LAN?
Configuring Jetty to accept connections from all hosts
I configured the server host to 0.0.0.0 from localhost to listen on all hosts. With this setting I can see on server start log,
INFO:oejs.AbstractConnector:Started SelectChannelConnector#0.0.0.0:8080
and it works only on http://localhost:8080 but it's not accessible from http://192.168.0.5:8080.
I also tried running that if the interface is accessible using the Networks Interface Listing as mentioned in this comment. and I got,
Display name: NETGEAR WNA1000M N150 Wireless USB Micro Adapter
Name: wlan4
InetAddress: /192.168.0.5
I also tried turning off my Windows Firewall/antivirus but din't help. My jetty version is <jetty.version>9.3.0.M1</jetty.version> and JDK 1.7. What could be the problem? Any help is appreciated.
McAfee Endpoint Security was the culprit here. It was blocking the requests with IP addresses from my very own computer. Turned off the firewall inside the Antivirus and I was able to access the site with http://192.168.0.5:8080/mysite from the browser and other devices connected through the network.
Sometimes some other program opens your port on external address before you do that with Jetty. It will receive all traffic instead. On Windows you will not know it if you reuse port (that is Jetty's default behavior). Check with netstat -ano what is the IP of the process that is indeed listening on 0.0.0.0:8080. Verify if it is your Jetty process only.
Then try connecting with telnet or netcat and see if you can open the connection and what is the response.
I have a web server running out of my home. I have assigned it an address such as 192.168.1.123 on port 80.
I understand that this is running on my local network. If I go to another computer on my network and type in the server's ip address, I can see the server.
Is there a way to access this server from outside my LAN?
Yes, you need to set your router to forward connections to port 80 to your internal IP address (192.168.1.123). Look for Port Forwarding on your router admin screen which I would imagine you access by going to http://192.168.1.1
Keep in mind that your ISP may block port 80 completely in which case you can run your web server on a different port (for example por 8180) and have your router forward connections to port 8180 to your internal IP.
To access your server from outside, you just need to point your browser to your external IP address which you can find out by going to http://www.ipchicken.com
Assuming you have a connection to the internet:
https://github.com/progrium/localtunnel
is a quick way to access your local server from the internet. There might be similar implementations in other languages/platforms. This is just the one I know about.
Remember that security issues need to be carefully considered when opening your local network to the world.
If you use a PHP Webserver you can set it this way:
php -S <YourIPAdresse>:<SomePortNumber> <StartPHPpage>
Example: „php -S 192.168.1.123:9000 index.php"