Telnet: Network is unreachable - ruby-on-rails

I'm new with Ruby on Rails, so I was trying to figure out how to send emails from the server.
I have followed several tutorial without success, so decided to check the basics and see if port 25 is open, I get the following line:
$ telnet example.com 25
Trying 93.184.216.34...
Trying 2606:2800:220:1:248:1893:25c8:1946...
telnet: Unable to connect to remote host: Network is unreachable
I have read about Conection refused but I can't figure out about unreachable is my port blocked or maybe my ISP?
Any help is useful

if you using ubuntu / debian based
check your server firewall and allow port 25
sudo ufw allow 25/tcp
1. install postfix if you want to build your own smtp server
2. other Alternatif
using gmail account as smtp server in rails , action mailer with gmail as smtp
or you can register to sendgrid.com as smtp server (not free but can apply testing account for one year trial)

Related

Connection Error in Guacamole: The remote desktop server is currently unavailable. If the problem persists, please notify your system administrator

I am trying to setup up guacamole in a Digital Ocean Droplet (Ubuntu 18.04). I followed the steps provided in https://computingforgeeks.com/install-and-use-guacamole-on-ubuntu/ to setup guacamole and used Postgresql to authenticate guacamole by following the instructions provided in https://guacamole.apache.org/doc/gug/jdbc-auth.html#idm46227496294336.
The installation got over and I am able to access the webpage at http://droplet-ip:8080/guacamole, but when I try to connect to a remote machine over RDP I get a connection error stating 'The remote desktop server is currently unavailable. If the problem persists, please notify your system administrator, or check your system logs.'
I have checked the login credentials of the remote device, it's hostip and RDP port number, everything is correct. I am able to login to the machine through Remote Desktop Connection in Windows. I can also login to the same remote machine with same credentials in a perfectly working guacamole setup in another digitalocean droplet.
I have also tried this by installing guacamole using docker by following instructions provided in https://wiki.networksecuritytoolkit.org/index.php/HowTo_Setup_Guacamole, but still face the same problem. What am I doing wrong? I would be happy if someone could help me solve this problem
I was finally able to figure out why I was not able to connect to a remote device in Guacamole.
My Digital Ocean Linux droplets had freeRDP already installed. But Guacamole Server 1.3.0 works on freeRDP2. I had to make Guacamole send requests through freeRDP2.
I have enabled SFTP in the connection settings. But somehow the OpenSSH was corrupted in the remote machine resulting in connection error. So, I disabled SFTP. I think guacamole tries to establish RDP and SFTP connection in the very beginning, so even if one of the protocols fail, connection cannot be established. I am not proficient with guacamole so not sure with this point.
After resolving these problems, guacamole was able to send connection request to the remote machine. I checked the status using netstat and the status was SYN_SENT, but there was no response from the remote server. The problem was Firewall.
I allowed the ports for RDP in windows firewall, but the remote machine was in a network which had external firewall. I added the Guacamole Server IP in allowed list for NAT forwarding in the firewall device and finally I was able to establish a connection with the remote machine.

Connecting to localhost via iPhone while connected to a hotspot

I need some help accessing a server that I have running on my mac. So basically my setup consists of mac on which I'm running my server and also using XCode to run the app on an iPhone connected via USB. And then both this iPhone and the mac are on the same wiFi network which is a personal hotspot that I have running on a different iPhone. I'm trying to access localhost from the iPhone by basically using my mac's IP address and the right port: http://IPADDRESS:PORT/, however this doesn't seem to work. Any ideas as to what may be going on here and potential workarounds or solutions. Connecting to a non hotspot, traditional wifi network is not an option at the moment.
Thanks!
This will work if you have it set up correctly; I am doing it right now. Remember that you have to bind the server to 0.0.0.0 — not 127.0.0.1 — if you want to connect from non-localhost IPs. Also check your system firewall.
If you're still having trouble, Tailscale is another solution that may help — https://tailscale.com
I suggest you take a look at using ngrok as a solution, this will create a secure tunnel and expose the service running on your Mac through a url.
You'll need to create an account and retrieve your auth token.
You can then install it using Homebrew by running in Terminal: brew cask install ngrok
Once installed, connect your account by typing into Terminal: ngrok authtoken [auth_token]
To start a tunnel, type into Terminal: ngrok [protocol] [port number]
For example, to start a tunnel to a HTTP server running on your mac: ngrok http 80 (or ngrok http 443 for HTTPS)
If its a custom TCP protocol use: ngrok tcp [port] (or ngrok tls [port] if using TLS)
This will then give you a URL to use in your app. On free accounts, the URL will change on each restart, paid accounts get a static URL option.
If you don't have Homebrew, download it from and follow instructions on: https://ngrok.com/download

What port to use sending email with SMTP (mailgun) in rails app on production server (DigitalOcean)?

I have a rails app deployed at a digital ocean droplet configured with capistrano and mailgun, but I'm having trouble sending emails, task which I do using delayed_jobs. The thing is every time it tries to send an email I get connection timeout (verified using RAILS_ENV=production bin/delayed_jobs runin the server) and I found out that for some reason digital ocean does not allow from default for you to access through port 587 (and indeed, running telnet smtp.mailgun.org 587 takes a very long time to access) but apparently trough port 2525 you can (mailgun also supports that port and running telnet smtp.mailgun.org 2525 connects instantly!). But again, it still gives me connection timeout, so I'm kind of confused and don't know what to do. I'll probably send a ticket to DO asking to open port 587, until then do you have any ideas?
Digital Ocean blocks SMTP for safety reasons, based on the CAN SPAM Act (https://www.ftc.gov/tips-advice/business-center/guidance/can-spam-act-compliance-guide-business), so if you want to send emails using SMTP in their servers you'll need to send a ticket asking to unblock it with some infos about yourself so they verify your not just some crazy guy trying to flood people mail boxes or a robot.
Hope it helps! Good luck

timeout when I try to ssh cpanel

I am trying to connect to the C panel server through ssh but I get a timeout.
What I have tried
I have tried ssh user#domain.com and user#ipaddress to no avail
I already tried using the ftp user account but the result is the same. I don't know what to do.
The goal
I have to connect in order to install rails on the server and this is a huge delay.
Please help.
the error is
ssh: connect to host xxx.co.ke port 22: Connection timed out
There are many possible reasons for this.
SSH is not configured on this port
SSH is not enabled on this server
The firewall on your server is blocking your IP
We will need more information like are you having a VPS or a shared hosting plan as many hosting companies do not allow ssh in shared hosting plans. If this is a VPS then you will need to ask your hosting provider the SSH port and try. Are you able to ping your server IP. If not, then you will also need to check in the server firewall if your IP is blocked.
You are using wrong SSH port OR your ISP ip is blocked on your server and due to that you are getting connection time out, You need to confirm your SSH server port from your hosting provider and ask them to enable SSH access for your cPanel user.

Jenkins email notification setup

I am trying to setup email notification for my jenkins server for build failures.
Things I have tried:
1) Use my company smtp mail server with authentication - does not work. Connection refused
2) Setup my own James mail server. SMTP server - localhost. Authentication - admin,admin. Port 25. I see that my SMTP server is running. - does not work. Connection refused
3) Use my personal gmail account with authentication - Works!!!
I have followed other discussions on this topic but not got an answer.
Some say it may be a firewall issue but I am not sure how to overcome it.
Any suggestions are most welcome.
Thanks,
I had the similar problem.
I was on wireless + windows 7 and when checked internet connectivity status, IPV4 was connected to internet but IPV6 was not.
Looks like IPV6 is used as default on windows 7 but it was not able to connect to the SMTP server using it.
Started my jenkins with -Djava.net.preferIPv4Stack=true and it worked for me.
java -Djava.net.preferIPv4Stack=true -jar jenkins.war and the "Test Configuration" worked.
For Sending Email Notifications using localhost SMTP server you need to install postfix,
For Linux :
sudo apt-get install postfix
telnet localhost 25
and then try sending test email. :)
I know this is late but just in case any other person is facing problem!

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