The remote Linux computer is in an internal network and has no public IP address. So I installed ngrok.
ngrok tcp 22
ngrok by #inconshreveable (Ctrl+C to quit)
Tunnel Status online
Version 2.0.19/2.0.17
Web Interface http://127.0.0.1:4040
Forwarding tcp://0.tcp.ngrok.io:36428 ->
localhost:22
Connections ttl opn rt1 rt5 p50 p90
0 0 0.00 0.00 0.00 0.00
I checked that sshd is running.
At the local PC, I tried
ssh myuser#ngrok.com -p36428
which gave rise to
ssh: connect to host ngrok.com port 36428: Connection refused
You are connecting to the wrong destination address. The command should be
ssh myuser#0.tcp.ngrok.io -p36428
Notice the different hostname (ie 0.tcp.ngrok.io instead of ngrok.com).
And generally you would want to put the user#hostname after all the options (eg -p36428), even though it doesn't generally cause any issues.
Related
I've got CRC running on Windows 11 and I would like to connect there from a RHEL9 VM.
CRC listening on 127.0.0.1:6443
Port forwarding rule created on Win machine to fwd connections on 192.168.1.156 (local intf) to 127.0.0.1:
$ netsh interface portproxy show v4tov4
Listen on ipv4: Connect to ipv4:
Address Port Address Port
192.168.1.156 9000 127.0.0.1 6443
Added rule in firewall to allow connections to port 9000
From the VM:
[test#workstation ~]$ telnet 192.168.1.156 9000
Trying 192.168.1.156...
Connected to 192.168.1.156.
Escape character is '^]'.
Connection closed by foreign host.
[test#workstation ~]$ oc login -u developer -p developer https://192.168.1.156:9000
The server is using a certificate that does not match its hostname: x509: certificate is valid for 10.217.4.1, not 192.168.1.156
You can bypass the certificate check, but any data you send to the server could be intercepted by others.
Use insecure connections? (y/n): y
Error from server (InternalError): Internal error occurred: unexpected response: 412
Any idea on how I can fix this and be able to connect from my VM towards CRC?
thanks
I know there are lots of resources on this topic, but I think I've done everything correctly and I still can't connect to my server.
I've started a simple node.js server on port 80.
sudo netstat -tnlp | grep 80
tcp 0 0 127.0.0.1:80 0.0.0.0:* LISTEN 3657/node
curl localhost:80
Welcome Node.js
I've configured the Security group for this instance as well as the VPC to allow traffic.
I've made sure there is no local firewall and that the VPC ACL is not blocking traffic (not that I expected it, since this is a completely new instance.)
service iptables status
Redirecting to /bin/systemctl status iptables.service
Unit iptables.service could not be found.
The output when I try to connect from my local machine:
curl 3.xxx.xxx.xxx
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- 0:00:03 --:--:-- 0
curl: (7) Failed to connect to 3.xxx.xxx.xxx port 80: Connection refused
Are there any other ideas on what to check next?
The answer to my problem was https://stackoverflow.com/a/14045163/2369000. The boilerplate code that I copied used a method to only listen to requests that originated from localhost. This could have been detected from the netstat output, which said 127.0.0.1:80 for the listening address. The answer was to use .listen(80, "0.0.0.0") or just .listen(80) since the default behavior is to listen for requests from any IP address.
I am unable to access Linux EC2 instance through SSH or browser-based SSH.
Instance id: i-01a3cdf3b36ff6d4f
Inbound rules:
HTTP TCP 80 0.0.0.0/0
SSH TCP 22 0.0.0.0/0
Outbound rules:
All traffic All All 0.0.0.0/0
Pls check below logs after running command from windows :
ssh -vvv -i "keypair.ppk" ec2-user#ec2-<IP>.ap-south-1.compute.amazonaws.com
C:\ProgramData\Microsoft\Windows\Start Menu\Programs\PuTTY (64-bit)>ssh -vvv -i "aws-lfd.pem" ec2-user#ec2-13-234-238-12.ap-south-1.compute.amazonaws.com
OpenSSH_for_Windows_7.6p1, LibreSSL 2.6.4
debug3: Failed to open file:C:\\Users\\b.tembhurne/.ssh/config error:2
debug3: Failed to open file:C:\\ProgramData\\ssh/ssh_config error:2
debug2: resolving "ec2-13-234-238-12.ap-south-1.compute.amazonaws.com" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to ec2-13-234-238-12.ap-south-1.compute.amazonaws.com [13.234.238.12] port 22.
I checked for config file it does not exist in above location. Do I need to create one manually? If so, What should it look like?
Pls help to resolve this issue.
A Connection timed out indicates that no response was received, which is typically caused by an incorrect network configuration (eg Security Group).
I would recommend that you start by launching a new Amazon EC2 instance in the same subnet, then check whether you can connect. This way, you'll know whether it is a network setting or a problem with the instance.
If that doesn't work, things to check are:
Instance is running Linux (so it can receive SSH requests)
Security Group is permitting inbound access on port 22 (SSH) from your IP address or 0.0.0.0/0
Instance is in a public subnet, which is defined as having a Route Table that points to an Internet Gateway
Your network needs to permit an outbound SSH connection (so try another network, such as home vs work, or tethered via your phone)
I have a:
Rasberry Pi 2
running
Raspbian Jessie Version:November 2015
I am using Undertow (a Java http server) to serve a website. This is the code that I use to build the server.
Undertow server = Undertow.builder()
.addHttpListener(8890, "localhost")
.setHandler(Handlers.pathTemplate()
.add("/", resource(new PathResourceManager(staticFilePath, 100))
.setDirectoryListingEnabled(false))
.build();
Problem: I am unable to see the webserver from another machine on the local network despite being able to ping and SSH into the PI.
What I have done (on the Pi2):
wget localhost:8890
returns the index.html correctly
netstat -lptn
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 -
tcp6 0 0 :::22 :::* LISTEN -
tcp6 0 0 127.0.0.1:8890 :::* LISTEN 1743/java
Chrome on my development machine 192.168.1.8:8890 gives
ERR_CONNECTION_REFUSED
wget 192.168.1.8:8890
Connecting to 192.168.1.8:8890... failed: Connection refused.
nmap 192.168.1.8
Starting Nmap 6.40 ( http://nmap.org ) at 2015-12-05 14:05 CST
Nmap scan report for 192.168.1.8
Host is up (0.039s latency).
Not shown: 999 closed ports
PORT STATE SERVICE
22/tcp open ssh
Nmap done: 1 IP address (1 host up) scanned in 1.83 seconds
It is my understanding that there is no firewall so I am baffled as to why I can't see the server from my development machine.
See:
tcp6 0 0 127.0.0.1:8890 :::* LISTEN 1743/java
Your web server listens only on localhost address (127.0.0.1). This way it couldn't be accessed from anywhere but localhost.
And your nmap scan shows the same: the only remotely accessible port is 22.
To access this service remotely you have to bind web server to any non-local address belonging to this raspberry pi (192.168.1.8) or to "any address" 0.0.0.0, as SSH service is bound.
How to do this is written in the manual of your web server. Probably, you have to start is with a "-d" param, i.e.
standalone.sh -b=0.0.0.0
standalone.sh -Djboss.bind.address=0.0.0.0
or something like this.
In listener setup code this looks like
"localhost" have to be replaced with some public name. This could be "0.0.0.0" or "192.168.1.8". We also can
cat "192.168.1.8 somename" >> /etc/hosts
and then use somename:
Undertow server = Undertow.builder() .addHttpListener(8890, "somename")
I have an application running on Windows machine. the application related alerts are to be e-mailed to administrator,for which an e-mail needs to be sent by Java program. The SMTP server is configured on a remote Linux machine in network.
The Java Mail program works fine and sends out an email, when run on the Linux machine. However if the same program is run on Windows it fails to connect to the SMTP server.
Note:
Ping to the Linux Machine (having SMTP server) is successful from Remote windows server.
Telnet < SMTP server hostname > 25 fails from remote machine as well from the machine where SMTP is running
Telnet localhost 25 is sucessful from SMTP server (Linux server).
The email by Java program is sucessfull, if run on SMTP server when hostname is specified as localhost.It fails if you give actual hostname.
/etc/hosts file on SMTP server lists 127.0.0.1 localhost.
How can i use the SMTP server to send an email from remote Windows machine?
I can paste the errors coming up on windows machine but the problem is not with the program; its the way the SMTP server is configured. I am new to SMTP so feel free to correct me if i am wrong.
The objective is to send a java e-mail from remote windows machine using the SMTP server on the Linux machine.
Adding the Output of netstat -ant|grep :25 as requested in the comment below:
[root#XXXXXXXXXXX]# netstat -ant | grep :25
tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN
tcp 0 0 ::1:25 :::* LISTEN
tcp 0 0 ::ffff:10.207.70.71:1521 ::ffff:10.207.70.71:25481 ESTABLISHED
tcp 0 0 ::ffff:10.207.70.71:25481 ::ffff:10.207.70.71:1521 ESTABLISHED
tcp 0 0 ::ffff:10.207.70.71:25202 ::ffff:10.207.70.71:3001 TIME_WAIT
tcp 0 0 ::ffff:10.207.70.71:25127 ::ffff:10.207.70.71:3001 TIME_WAIT
tcp 0 0 ::ffff:10.207.70.71:25289 ::ffff:10.207.70.71:3001 ESTABLISHED
tcp 0 0 ::1:51432 ::1:25580 ESTABLISHED
tcp 0 0 ::1:25580 ::1:51432 ESTABLISHED
tcp 0 0 ::ffff:10.207.70.71:25233 ::ffff:10.207.70.71:3001 TIME_WAIT
tcp 0 0 ::ffff:10.207.70.71:3001 ::ffff:10.207.70.71:25289 ESTABLISHED
[root#XXXXXXXXXXX]#
Postfix: Accepting SMTP connections on ALL IP interrfaces
Your SMTP server (postfix) accepts incoming SMTP connection only on loopback interface(s)
[IPv4=127.0.0.1 and IPv6=::1].
Make your postfix listen on all available IP interfaces -> in main.cf configuration file restore default setting inet_interfaces = all
http://www.postfix.org/postconf.5.html#inet_interfaces
Why "loopback only" configuration is used?
Limiting SMTP server to accept only local SMTP connections is pretty common default configuration on "workstations". It allows sending emails (e.g. system warnings/notifications) without accepting any incoming spam.