Tag: linux server

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Simple SSH Tunnelling tips

SSH tunelling is usually used to avoid firewall restriction or to ensure point-to-point encrypted communication.

For example, if you want to send email to smtp server “smtp.yourserver.com” on port 587, but your organization currently blocking smtp port 25 and 587, then you can benefit from SSH tunelling to avoid from being blocked.

To get around that, you need an intermediate server, fastssh.com currently provide SSH tunneling service with 7days trial account.

Simple SSH tunnelling command, if you’re using fastssh.com service.

ssh -f fastssh.com-username@sg.fastssh.com -L 2000:smtp.yourserver.com:587 -N

So in your mail setting, you can safely put, SMTP Server = “127.0.0.1”, SMTP port = “2000” in your setting, in order to automagically connect to “smtp.yourserver.com” port 587 without firewall restriction.

Please refer here, for port forwarding in Microsoft Windows environment using PuTTY

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Restricting normal user account access on Ubuntu Server

Here’s a tip to restrict normal user account access so that common users may not be able to explore other directories beyond his/her own /home directory.

  • First you need to chmod all /home dir to 0700
  • Then, you need to set the default umask to 077, to do that, you ned to edit /etc/profile, and replace “umask 022” with “umask 077“.
  • Optionally, you can also update PAM configuration in /etc/pamd.d/common-session so that the line reads “pam_umask.so umask=077 usergroups“

The tips has been adapted from – superuser.com