Category: Linux

How to sync two FreeNAS storage using rsync

FreeNAS supports rsync and that’s one of the most interesting feature of the operating system. rsync is a protocol for file synchronization and transfer, a really useful tool in a storage device. Continue reading


So sánh các giao thức VPN: PPTP vs. L2TP vs. OpenVPN vs. SSTP vs. IKEv2

Các kỹ thuật mã hóa VPN được phát triển và chứng nhận bởi National Institute of Standards and Technology, tuy nhiên với vụ Edward Snowden tiết lộ về các bị mật mà NSA đang cố gắng bẽ khóa công nghệ này là một thông tin gây sốc. Điều này đặt dấu chấm hỏi liệu   “các công nghệ VPN này có thực sự bảo mật”? Và để trả lời cầu hỏi này, chúng tối nhận thấy đây là thời điểm để viết về chủ đề này.

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Install OpenVPN on Ubuntu 16.04


If you want more than just pre-shared keys OpenVPN makes it easy to setup and use a Public Key Infrastructure (PKI) to use SSL/TLS certificates for authentication and key exchange between the VPN server and clients. OpenVPN can be used in a routed or bridged VPN mode and can be configured to use either UDP or TCP. The port number can be configured as well, but port 1194 is the official one. And it is only using that single port for all communication. VPN client implementations are available for almost anything including all Linux distributions, OS X, Windows and OpenWRT based WLAN routers.

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Config NAT with iptables in linux

6.1 Source NAT


You want to do Source NAT; change the source address of connections to something different. This is done in the POSTROUTING chain, just before it is finally sent out; this is an important detail, since it means that anything else on the Linux box itself (routing, packet filtering) will see the packet unchanged. It also means that the `-o’ (outgoing interface) option can be used.

Source NAT is specified using `-j SNAT’, and the `–to-source’ option specifi Continue reading