Tag Archives: openwrt

Post related to Openwrt routers and their software

Providing IPv6 DNS resolver data with radvd

One nagging issue I had with IPv6 was how to distribute DNS server addresses and search lists to my clients.   It took a little research to find the solution.  On IPv4 I had been using DHCP to do this, but DHCP didn’t seem to be right approach for IPv6. radvd can be used to distribute both types of data.  The following article covers setup on Ubuntu and OpenWRT.  The Ubuntu (Debian) examples below should work with any distribution using/etc//radvd.conf to configure radvd. Continue reading

Implementing IPv6 Part 2

We are quickly running out of IPv4 addresses. Are you ready for World IPv6 Day on June 8th, 2011? I have prepared my configuration on OpenWRT and Ubuntu. This includes configuring DNS using bind, email using Exim, and a Squid web proxy.

Having verified that I could establish IPv6 connectivity, I chose to improve my connectivity. This started with getting a tunnel from Hurricane Electric and updating my configuration. I then updated my bind server and Exim mail server support IPv6 addresses. This posting updates and continues from my post on Implementing IPv6 6to4 on OpenWRT.   Review it for information on creating a tunnel and running radvd on OpenWRT. Continue reading

Transparent Squid Proxy

Over the holidays, I had a user experience and attempted browser hijacking.  It appeared to have bypassed my squid proxy.   My updated configuration now sends all web access via squid.  The old firewall rules, that allowed direct access to the Internet, have been replaced with a transparent Squid proxy.  This runs on my existing Squid Proxy using another port. Continue reading

Implementing IPv6 6to4 on OpenWRT

As the IPv4 addresses begins to run out I finally invested the time to investigate and implement IPV6. As my ISP has not yet announced availability of IPV6 addresses I chose to implement a 6to4 tunnel. This is simple to implement, and currently well supported. My external firewall is an ASUS wireless router running OpenWRT.  As I have a static IP address, my implementation is simpler than is required by a dynamic address.  Support for dynamic IPv4 addresses is not covered here, but this configuration should work as long as your address does not change.

I initially created a 6to4 implementation without a firewall.  Then to secure my systems I implemented a firewall using Shorewall6-lite.  Until I figured out how to configure the 6tunnel script, I used the command line to bring up the network.  This documentation uses of the 6tunnel script instead of the manual commands.  My configuration does not yet include any IPsec functionality. Continue reading

Firewalling Google Chat and Skype

To enable for Internet chat I set up Google Chat and Skype.  My firewall rules have been extremely restrictive with only known and approved services allowed to connect.  Google Chat installed with no noticeable impact to the firewall. Things did not go so well with Skype.

The installation of Skype resulted in lots of warnings on the firewall.  Outgoing tests worked with only port 80 and 443 open.  Skype’s peer-to-peer approach  requires at least one port be opened incoming and and a large range of ports outgoing.  They specify all ports over 1024 should be open.  Their preferred mode seems to be to use uPnP to dynamically modify the firewall.   They do allow you to attempt to set  fixed incoming port which is also used for some outgoing UDP traffic. Continue reading

Monitoring with Munin

Munin is a system monitoring program designed to capture and graph performance statistics with minimal configuration. It is significantly easier to configure than MRTG and has a wide variety of plugins.  The Ubuntu (Debian) installer will setup a reasonable configuration on installation.  It requires one server, and a client daemon on all monitored servers including the server. Scalability to large (campus) environments has been reported to be an issue Continue reading

OpenWRT and Ubuntu dnmasq setup

Now I have replaced my old firewall with OpenWRT, I needed to enhance the configuration of dnsmasq to support the network.  The old Ubunutu based firewall was already running dnsmasq, as does the DNS server on the LAN.

I run a mixed network with wired and wireless clients on separate address ranges. DHCP services are provided by the OpenWRT router. An Ubuntu server is the primary DNS server for the wired network. Continue reading

OpenWRT syslog-ng Installation

When I went to process my remote firewall log output from OpenWRT, I noticed that the entries were truncated.  A quick check with tcpdump indicated that the syslog packets were truncated to 256 characters.  As syslogd and klogd are both provided by BusyBox, I decided to replace them both.  The obvious solution was to replace them with syslog-ng.  opkg indicated that it was available, so installation was simple.

Unfortunately, configuration is not yet automated.   A default configuration file is provided in /etc/syslog-ng.   This simply logs to /var/log/messages.  It also assumes that klogd is active.  After some research and experimentation, I came up with a configuration. It can provide a local log in /var/log/messages. More importantly it provides complete firewall log entries to the remote server. Continue reading