28 Apr 09 brctl: Creating a network bridge

Creating a layer 2 ethernet bridge under Debian (or Linux in general really) is incredibly easy, as are most things. What a L2 bridge actually is, is outside the scope of this guide, however Google has plenty of information. Essentially, ethernet frames are mirrored between the two interfaces, therefore what Layer 3 protocol data (TCP, UDP, ICMP, etc) is within the ethernet frame is irrelevant. Anyway, back to the point..

In case you don’t have the package, apt-get install bridge-utils and you’ll also need bridge support in your kernel, however unless you specifically removed it, you should have it.
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Tags: brctl, bridge, bridge-utils

19 Oct 08 Linux on a Mikrotik 532a , Part 5 Final – OpenWRT and Custom Scripts

Follow on from: http://www.adamsinfo.com/linux-on-a-mikrotik-532a-part-4-customization-debian-scripts-shaping-firewall-nat-picolcd/

Discuss this article here

I’ve used OpenWrt previously to this project to build some firmwards for the Linksys Router WRT54 range. OpenWrt is an incredibly powerful and small Linux distro. Although debian is probably better suited to the reasonably powerful hardware, I wanted to give OpenWrt a go anyway.

Unless you’re running a MIPS 4Kc processor on your host which I’m guessing you’re not, you’ll either need to cross compile your binaries, or just compile them natively on the device itself. Compiling on the device works fine as long as you have the relevant packages, however if I was going to build a 2.6 kernel, I’d rather do it on an x86 quad core intel host, rather than waiting a week for the device to do it. I also wanted to minimize the writes on the CF card.

OpenWrt comes with a nice buildroot environment which you can read about and download from www.openwrt.org using Subversion.

Here http://downloads.openwrt.org/kamikaze/docs/openwrt.html#x1-310002 is a great HOWTO on getting the build root environment set up on your x86 host.

Also, see: http://wiki.mikrotik.com/wiki/RB500_Linux_SDK – this is a very complete HOWTO, which is why I’ve not covered most of the installation process and just detailed customizations.

You’ll need to select the RB5xx target for the kernel. Also, run:

In your build root top directory, and add USB support (as my one is modded for USB which is not RB5xx default.

While you’re there, browse to the networking options and make sure you have everything you want, specifically the schedulers for traffic shaping.

Here is my precompiled image:

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Tags: /dev/cfa1, /dev/cfa2, /dev/cfa3, bridge, build root, buildroot, debian, dropbear, ifconfig, iptables, kamikaze, mikrotik, miniupnp, miniupnpd, mips 4kc, multiple isps, multiple providers, ntp, ntp client, openwrt, precompiled image, rb532a, rbxxx, split route, subversion, svn kernel, uplink, usb, usb support, x86

11 Oct 08 Linux on a Mikrotik 532a, Part 4 – Customization, Debian Scripts, Shaping, Firewall, NAT, picoLCD

Follow On From: 05 Oct 08 APNIC Box – Linux on a Mikrotik 532a, Part 3 – Installing Debian, Prebuilt Disk Image

Following on from the previous article, I’ve written some scripts which you’ll find in the /root/scripts/ directory of the prebuilt image. I’ve attached and commented them here, as they could also be useful elsewhere.

bridge.sh #For setting up a simple bridge
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Tags: 532a, APNIC Box, bandwidth management, bandwidth rate, bridge, cbq, ifconfig, iproute2, iptables, lcd, Linux, picolcd, qdisc, routerboard, routerboard 532a, shaping, tc, time, usblcd, usleep

26 May 08 Custom linux router, routing, split access and more..

So, now I have got this router set up and working, it was time to customize it somewhat.

In terms of networking, we have 3 10/100 ethernet ports and one wireless adapter, and this is set up as follows:

Internet comes in to eth1 and eth2, both of which have public IPs. eth0 which is another ethernet interface is bridged with ath0 which is my wireless interface (in master mode, with WPA-PSK/TKIP with hostap running) to form br-lan, whos IP is 192.168.100.1and is connected via a switch to feed the LAN PCs

I’m using a pretty simple netfilter masquerade script in use with this for NAT.
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Tags: bridge, ethernet, hostap, IP, load balance, multiple providers, router, split access, upnp, wireless, wpa