Book Image

Linux for Networking Professionals

By : Rob VandenBrink
1 (1)
Book Image

Linux for Networking Professionals

1 (1)
By: Rob VandenBrink

Overview of this book

As Linux continues to gain prominence, there has been a rise in network services being deployed on Linux for cost and flexibility reasons. If you are a networking professional or an infrastructure engineer involved with networks, extensive knowledge of Linux networking is a must. This book will guide you in building a strong foundation of Linux networking concepts. The book begins by covering various major distributions, how to pick the right distro, and basic Linux network configurations. You'll then move on to Linux network diagnostics, setting up a Linux firewall, and using Linux as a host for network services. You'll discover a wide range of network services, why they're important, and how to configure them in an enterprise environment. Finally, as you work with the example builds in this Linux book, you'll learn to configure various services to defend against common attacks. As you advance to the final chapters, you’ll be well on your way towards building the underpinnings for an all-Linux datacenter. By the end of this book, you'll be able to not only configure common Linux network services confidently, but also use tried-and-tested methodologies for future Linux installations.
Table of Contents (20 chapters)
1
Section 1: Linux Basics
4
Section 2: Linux as a Network Node and Troubleshooting Platform
8
Section 3: Linux Network Services

Remote port enumeration using native tools

So now we know how to work out our local services and some traffic diagnostics, how can we enumerate listening ports and services on remote hosts?

The easy way is to use native tools – for instance scp for SFTP servers, or ftp for FTP servers. But what if it's some different service that we don't have an installed client for. Simple enough, the telnet command can be used in a pinch for this – for instance, we can telnet to a printer's admin port, running http (tcp/80), and make a GET request for the header of the first page. Notice the garbage characters at the bottom of the listing – that's how graphics are represented on this page:

$ telnet 192.168.122.241 80
Trying 192.168.122.241...
Connected to 192.168.122.241.
Escape character is '^]'.
GET / HTTP/1.1
HTTP/1.1 200 OK
Server: HP HTTP Server; HP PageWide 377dw MFP - J9V80A; Serial Number: CN74TGJ0H7; Built: Thu Oct 15, 2020 01:32...