cron
and at
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Network transparency is one of the central characteristics of a Unix system. X, the windowing system of Unix operating systems, can use this feature in an impressive way. With X, it is no problem to log in to a remote host and start a graphical program that is then sent over the network to be displa…
OpenSSH is the SSH (secure shell) implementation that ships with SUSE Linux Enterprise Server, for securing network operations such as remote administration, file transfers, and tunneling insecure protocols. SSH encrypts all traffic, including authentication, to protect against eavesdropping and connection hijacking. This chapter covers basic operations, plus host key rotation and certificate authentication, which are especially useful for managing larger SSH deployments.
Whenever Linux is used in a network environment, you can use the kernel functions that allow the manipulation of network packets to maintain a separation between internal and external network areas. The Linux netfilter framework provides the means to establish an effective firewall that keeps differ…
Today, Internet connections are cheap and available almost everywhere. However, not all connections are secure. Using a Virtual Private Network (VPN), you can create a secure network within an insecure network such as the Internet or Wi-Fi. It can be implemented in different ways and serves several purposes. In this chapter, we focus on the OpenVPN implementation to link branch offices via secure wide area networks (WANs).
Managing your own public key infrastructure (PKI) is traditionally
done with the openssl
utility. For admins who
prefer a graphical tool, openSUSE Leap 15.3 includes XCA,
the X Certificate and Key management tool
(http://hohnstaedt.de/xca).
XCA creates and manages X.509 certificates, certificate requests, RSA, DSA, and EC private keys, Smartcards, and certificate revocation lists (CRLs). XCA supports everything you need to create and manage your own certificate authority (CA). XCA includes customizable templates that can be used for certificate or request generation. This chapter describes a basic setup.
sysctl
variablesSysctl (system control) variables control certain kernel parameters that influence the behavior of different parts of the operating system, for example the Linux network stack. These parameters can be looked up in the proc file system, in /proc/sys. Many kernel parameters can be changed directly by …
If your organization does any work for the United States federal government, it is likely that your cryptography applications (such as openSSL, GnuTLS, and OpenJDK) will be required to be in compliance with Federal Information Processing Standards (FIPS) 140-2. FIPS 140-2 is a security accreditation program for validating cryptographic modules produced by private companies. If your organization is not required by compliance rules to run SUSE Linux Enterprise in FIPS mode, it is most likely best to not do it. This chapter provides guidance on enabling FIPS mode, and links to resources with detailed information.