Start AutoSSH on System Startup Using Systemd on Arch Linux

 Arch Linux, Networks  No Responses »
Mar 272013
 

OK, here is how to start ssh on system startup (this is the content of the systemd .service configuration file /etc/systemd/system/autossh.service):

[Unit]
Description=AutoSSH service for a reverse tunnel from some.example.com to localhost
After=network.target

[Service]
ExecStart=/usr/bin/autossh -M 0 -q -N -o "ServerAliveInterval 60" -o "ServerAliveCountMax 3" someuser@some.example.com -R 1250:localhost:8080

[Install]
WantedBy=multi-user.target

After creating the systemd .service file do:

systemctl daemon-reload
systemctl status autossh.service
systemctl restart autossh.service
#Enable autossh.service to be started on bootup:
systemctl enable autossh.service

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Dynamic Routing with BIRD Running the IPv6 based OSPFv3 Protocol on OpenWrt

 Networks  3 Responses »
Dec 192012
 

This is somehow a follow up of the older post IPv6: Dynamic Routing with Quagga and ospf6d (OSPFv3).

I’m switching from Quagga to BIRD to manage dynamic routing using the OSPFv3 protocol on my networks. BIRD is a slim routing daemon in use by quite some internet exchange points now. You can read more about it on its Wikipedia article.

In OpenWrt

OpenWrt files bird as two packages: bird4 with IPv4 capabilities and bird6 with IPv6 (and NO IPv4) capabilities. See this for further information on the separation into two packages.
So the installation of BIRD for IPv6 on OpenWrt works like this:

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A Collection Of Reliable Public DNS Servers

 Networks  No Responses »
May 012012
 

TODO: Write a script to ping all the IPs and find the best (fastest). Put it online as a gist on GitHub.

Google

http://code.google.com/speed/public-dns/docs/using.html

  • 8.8.8.8
  • 8.8.4.4

IPv6:

  • 2001:4860:4860::8888
  • 2001:4860:4860::8844

Level3 / AT&T

  • 4.2.2.1
  • 4.2.2.2
  • 4.2.2.3
  • 4.2.2.4
  • 4.2.2.5
  • 4.2.2.6

More

  • 195.92.195.90 – Orange DNS (ISP)
  • 156.154.70.1 – DNS Advantage

OpenDNS

use.opendns.com
www.opendns.com/ipv6

  • 208.67.222.222
  • 208.67.220.220

IPv6:

  • 2620:0:ccc::2
  • 2620:0:ccd::2

Freenet6

IPv6:

  • 2001:5c0:1000:11::2
  • 2001:5c0:1001::194

How To Find Out Who’s Operating a DNS Server

Run whois on the IP:

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OpenWrt on a TP-Link TL-MR3020 Router

 Networks, Other Hardware, Other Linux  1 Response »
Mar 172012
 

This is a really compact and cheap router to take with you to hotels etc. to secure your internet access via VPN or redistribute a network.

The Hardware

You can get some information on the used hardware from my /proc/cpuinfo, /proc/meminfo and dmesg.

I put some photos I made of the PCB online on this PicasaWeb album.

More details to be found in OpenWrt’s wiki page on the router.

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Generate Bind Reverse Zone File Using A Simple Python Script

 Networks  No Responses »
Mar 112012
 

When I had to create a reverse DNS zone file for my Bind name server I wanted it to be as flexible as possible and thus created a Python script that generates the Bind zone file. This makes renumbering the network really easy.

The script is available as a gist on Github:

To create the zone file, customize the configuration section in the script. Then run it and the output to stdout should be sent to the zone file:

./rdns.py > /etc/bind/db.your.zone.name

The default output (of the example config settings) would look like this:

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Make RS232 Serial Devices Accessible via Ethernet

 Networks, Other Hardware  1 Response »
Aug 222011
 

Standards

The RFC 2217 standardizes the transmission of serial connection data via Ethernet, allowing to change remote serial port parameters (such as speed, parity, stop bits) over TCP using NVT (Network Virtual Terminal).

Implementations

Connection between your serial device and the Ethernet

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Query DNS on MS Windows

 Networks  No Responses »
Jul 092011
 

To query a DNS entry for a domain name, here www.example.com run this command on the Windows PowerShell:

[System.Net.Dns]::GetHostAddresses("www.example.com")

And the opposite, get a hostname from an IP address:

[System.Net.Dns]::GetHostbyAddress("207.46.198.30")

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IPv6 Adresses

 Networks  No Responses »
May 162011
 

Defined in RFC 5156

  • ::1/128 is the loopback address
  • ::/128 is the unspecified address
  • ::FFFF:0:0/96 are the IPv4-mapped addresses (indicating devices that are not IPv6-capable)
  • ::<ipv4-address>/96 are the IPv4-compatible addresses, deprecated!
  • fe80::/10 are the link-local unicast addresses
  • fc00::/7 are the unique-local addresses
  • 2001:db8::/32 are the documentation addresses. They are used for documentation purposes such as user manuals, RFCs, etc.
  • 2002::/16 are the 6to4 addresses
  • 2001::/32 are the Teredo addresses
  • ::/0 is the default unicast route address
  • ff00::/8 are multicast addresses

See “Special-Use IPv6 Addresses” (RFC 5156): http://tools.ietf.org/html/rfc5156

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Get your own DNS server up and running with Bind9 on Ubuntu or Debian

 Debian, Networks, Ubuntu 10.10  4 Responses »
Apr 112011
 

The goal of this article is to describe how to setup your own DNS server to serve the domain name service entries for a TLD (example.com). In the last part of the article I describe how to increase the speed of the system and the security in order to use it as public authoritative DNS nameserver for your domain.

Install the Nameserver using the Package Manager

Access the server, become the root user, install the bind9 package and stop the server for the moment:

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