Email sender fraud is an annoying problem. Malicious email senders send spam emails with email senders that are under non-authorized domain names. This may affect the reputation of the domains used by the fraud sender. On another hand, lots emails will be rejected and reverted back, which causes lots additional work to the domain administrators.
Read more
Category: Network
Network-related posts.
How to synchronize OneDrive and OneDrive for Business files in Linux using Insync
Posted onOneDrive is one of the good cloud storage services available and there is a business version called OneDrive for Business. Microsoft’s Office 365 plan is widely used including Exchange Email service and OneDrive for Business. However, there is no official client released yet for Linux users. Insync is a third party cloud storage syncing software
Read more
How to synchronize Google Drive and Google Docs files in Ubuntu/Debian/Mint Linux using Insync
Posted onGoogle Drive is a nice cloud storage service. It provides a suite of nice online document spreadsheet and slide editors Google Docs, Google Sheets and Google Slides. The collaborative editing and full history tracking features of Google Docs are excellent. Google Drive gives 16GB free storage which is pretty much larger compared to other free
Read more
Allowing root Access to NFS Directories
Posted onFor local filesystems, root usually has full access (read/write) to directories/files inside of it. But for NFS directory mounted from network, root usually has no permission to write to directories or files within the NFS directory. How to make root act similarly in an NFS directory to the behavior in local directories? The reason that
Read more
QEMU/KVM Network Mechanisms
Posted onIntroduction As we know, network subsystems are important in computer systems since they are I/O systems and need to be optimized with many algorithms and skills. This article will introduce how QEMU/KVM [2] network part works. In order to put everything simple and easy to understand, we will begin with several examples and then understand
Read more
How to Change Linux Account Password Through SSH: A Beginners’ Tutorial
Posted onPeople are sometimes given access to Linux/Unix and asked to change their initial passwords. But for beginners, changing a Linux/Unix password is not an easy task, especially when there is only SSH log on allowed to the Linux/Unix server. This post introduces how to change password of user USER on host HOST remotely using SSH.
Read more
How to Set the Static IP Address Using CLI in Fedora/CentOS Linux
Posted onHow to set the static IP address for CentOS 7/Fedora 22+ is introduced in this post. Here, we assume the Linux is using NetworkManager to manage the network. All steps are done as root. Find the interface you want to set the address Command ifconfig -a lists all interfaces. Find the interface name to set,
Read more
Keeping Linux SSH Session Alive from Disconnecting – Server and Client Side Fixes
Posted onSSH is a very common tool for Linux/Unix platforms. One annoying problem when using SSH is that the connection may get disconnected if the SSH connection is idle for some time under common configurations. Users may run an infinite loop like while true; do uptime; sleep 30; done when there is no work to be
Read more
Blocking JavaScripts from a Site in Chrome in 2 Easy Steps
Posted onYou may be aware of the GitHub’s largest DDoS attack in history on Mar. 27, 2015 (some context, technical details, and discussions): We've been under continuous DDoS attack for 24+ hours. The attack is evolving, and we're all hands on deck mitigating. — GitHub Status (@githubstatus) March 27, 2015 One important technique when facing this
Read more
Free VPNs for iPhone Users: OpenVPN + Ovpn Spider
Posted onVPNs are useful for testing viewing webpages from a remote location or visiting blocked websites. In this post, I will introduce a method for finding and using free VPNs on iPhone. Note that the VPNs are free and the providers are not identified. Hence, only use this method for visiting public webpages or keeping visiting
Read more
iPhone Connecting to Internet Using Windows PC’s Network through USB Cable
Posted onNote that this was only tested on certain combinations like this (Windows 7 with iOS 8), this (Windows 7 with iOS 7), this and this (Windows 7 with iOS 9.3.2 (iphone 6s)). Windows 7 seems a possible Windows OS that can work. Recently, I tested it on Windows 8 and iOS 9. Unfortunately, it did
Read more
Lazy Linux Admins Going to Server Rooms Less: Forced Reboot, Auto Reboot after Kernel Panic and Email Notification after Reboot
Posted onHaving to go the the server room to reset servers is the most headache thing for admins managing a cluster of Linux servers in a remote site. Either you can ping the server but can not ssh to it, or you even can not ping it. There are various reasons that may cause a Linux
Read more
How to Play Movie from Remote Host using MPlayer over SSH
Posted onMPlayer is a great movie player. SSH is a great tool to connect and transfer data over the network securely. Combining these 2 great tools together will be greater. You may already has a small server storing some movies or videos or music and playing them on your laptop will be convenient. In this post,
Read more
Git through SSH Tunnel as Proxy
Posted ongit is a great tool and it is common to have a git server over SSH possibly managed by gitolite. However, there are situations that we can not directly connect to the git server but be able to SSH to another node that can connect to the git server. The git server may allow only
Read more
Improving ssh/scp Performance by Choosing Suitable Ciphers
Posted onUpdate on Oct. 9, 2014: You should be aware of the possible security problems of blowfish and it is suggested not to be used. Instead, you may consider ChaCha20 as suggested by Tony Arcieri. To use this with OpenSSH, you need to specify the Ciphers in your .ssh/config files as chacha20-poly1305@openssh.com possibly with another default
Read more
How to Set Up A Gitolite Git Server – A Ten-Minute Tutorial
Posted onI ever introduced seting up git server using SSH or gitosis. However, gitolite is the way to go for managing git servers if you want an lightweight authentication layer. gitolite provides many very usefull features which can control each user’s right on each branch. I set up one gitolite git server and am very happy
Read more
How to Connect to Remote Servers by VNC on Windows
Posted onSoftware you will need 1, Putty 2, Real VNC viewer 3, twm (lightweight desktop). On fedora (centos, redhat): sudo yum install twm (on other distros, you may need other commands, or download source code and install it). Specific steps 1, Enter your Host name and port in putty. 2, Set port forwarding in putty Tunnels.
Read more
Fixing Ports Used by NFSv3 Server
Posted onThe ports used by NFS server can be dynamically assigned by rpbind to any higher number. We need to fix the ports used by NFS server to configure firewall or port forwarding mechanism. The ports used by NFS server and how to fix these ports will be introduced in this post. There are seven ports
Read more
How to Configure iOS to Use Socks Proxy over SSH with a Linux/Unix Host
Posted onThe socks proxy I created following Proxy Using SSH Tunnel works very well on both Linux and Windows. However, when I try to configure my iPhone and iPad with iOS, I find iOS does not support socks proxy in its settings interface. I don’t know why it is not added while socks proxy is indeed
Read more
How to Flush iptables on Fedora Linux
Posted oniptables is a mechanism in Linux kernel for port forwarding, NAT, firewalls etc. In Linux distros, such as Fedora, the iptables is configured to be as a “strict” firewall that opens a limited know ports, such as 22 for SSH. However, in some network environment, such as a private cluster, the nodes are trusted and
Read more