Showing posts with label Network. Show all posts
Showing posts with label Network. Show all posts

Friday, March 01, 2013

Automatic US / UK VPN connection with XBMC, iPlayer, Hulu and Free Cable

XBMC has addons for various geolocked services, Hulu and iPlayer being among most popular. Switching between VPN connections manually gets boring quick so I hacked following script that will automatically connect and disconnect VPN to US / UK on demand. Tested with XBMCbuntu and XBMC 12.0 Frodo.

Monday, February 11, 2013

Measuring one-way network latency, jitter and packet loss on Linux

Ping can tell you round-trip or two-way latency, but if you want to know if it's upstream of downstream that's slowing down you need something else. You need OWAMP (One-Way Ping).

Saturday, July 07, 2012

Quick and dirty OpenVPN bridge configuration

Quick and dirty configuration to bridge two ethernet segments using OpenVPN. With this setup you need two ethernet interfaces per host or alternatively one ethernet and wireless access to Internet.

Sunday, January 22, 2012

SMTP NAT with Sendmail

This post is closely related to my previous one. Big difference is that in this case company we bought had Lotus Notes based email system that had to be kept running concurrently with new common email platform for several months. Well, actually it is still running to some extent over 4 years later but that's another story.

Simple fetchmail config

Few hours ago you got called to meeting with your boss. You were told that company you're working for just bought another firm and everything needs to be integrated ASAP starting with unifying email addresses.

Thursday, January 19, 2012

Reliable IP over multiple unrealiable IP links with Linux and Strongswan

Some time ago I wrote about how to make multiple unreliable Internet connections function like single reliable Internet connection. That was done using OpenVPN and some iptables trickery. This time we're going to do same without OpenVPN and without iptables.

Wednesday, January 18, 2012

Linux multipoint GRE tunneling

Here's another interesting little known feature of Linux kernel GRE support.

Layer 2 over Layer 3 using Linux built-in features

Often it's not necessary to encrypt traffic when tunneling L2 network over L3 in corporate environment. I hear, you say use OpenVPN, tinc, gvpe, n2n etc. Now, did you know that there's easy built-in solution that has been part of Linux kernel since 2.6.29? If you need encryption just use IPsec to protect GRE traffic.

Monday, January 09, 2012

Planet WNAP-7300 (Zcomax ZCN-1523H-5) with OpenWrt r29664

It turned out to be just like I suspected, Planet WNAP-7300 (at least with firmware "2.0.3(PL)4") is exactly same device as Zcomax ZCN-1523H-5. Atheros AR7240 rev. 2 at 350MHz, Atheros AR9280 rev 2 5GHz radio, 32MB RAM, 8MB Flash and two 10/100 Ethernet ports. Therefore it works with Zcomax OpenWrt firmware. Bridge performance seems acceptable, around 70Mbit/s real world in bridged mode and 60Mbit/s if OpenWrt is doing NAT. With around 25 meters nearly line-of-sight performance is ~40Mbit/s. All tests uni-directional TCP (FTP/HTTP) with no other traffic than ICMP echo going on at the same time.

Using dy.fi dynamic DNS with OpenWrt

Didn't see this documented anywhere so here it is. How to use Finnish dy.fi dynamic DNS service with OpenWrt router.

Saturday, January 07, 2012

Strongswan 4.6.2dr3 on Ubuntu 12.04 alpha 1

For some reason latest Strongswan version for Ubuntu is still 4.5.1. See below how to compile and package latest 4.6.2dr3. Not pretty, but works for me when testing new version.

Friday, December 30, 2011

(Ab)using OpenVPN to make two unrealiable Internet connections act asone reliable connection (Success!)

Hi, I'm Troy McClure. You might remember me from such posts as Failure #1 and Failure #2. Today I'm here to tell you about "OpenVPN inside OpenVPN".

(Ab)using OpenVPN to make two unrealiable Internet connections act asone reliable connection (Failure #2)

We mirror our hard disks, we mirror RAM on servers. Why not mirror network traffic as well? 

(Ab)using OpenVPN to make two unrealiable Internet connections act asone reliable connection (Failure #1)

Got packet loss? Got two or more connections? Got server somewhere to route packets thru?