Linux - SecurityThis forum is for all security related questions.
Questions, tips, system compromises, firewalls, etc. are all included here.
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
I have tested this in the past and the result always was that my PC is invisible, because it does not respond to ping and all ports are in stealth mode. However, when I ran the test today I found that it responds to ping and port 113 IDENT is closed instead of stealth.
Does anybody know how I can make this port invisible too and how I can make my computer clear not to respond to pings? Might there be updates (SuSE or KDE) that changed the security level?
In SuSE 9.3 you can edit /etc/sysconfig/SuSEfirewall2 to stealth port 113. I had the same report from ShieldsUP!, and editing the settings for this port and the policy for ping (Note: on a standalone PC) now give me 100% stealth result from Gibson's security test. There is lot of comment in SuSEfirewall2 to help you along.
You seem to allow icmp which ping uses, and reject port 113 instead of dropping or just plain not including it in the script. Like bibh_lnxq said, have a look at your firewall script. icmp is needed for some stuff though, like scp transfers with fish, so you might want to consider allowing it.
btw, not everyone feels shieldsup is a good test http://www.grcsucks.com/
The scan results are likely correct. SuSE intentionally leaves ident as CLOSED rather than stealthed for a reason. Certain services (like irc and some ftpd) require that queries to the clients ident port return at least some type of response before a connection is allowed. If SuSE left it closed then certain services would break for some users.