[DLSLUG-Discuss] DLSLUG Meeting, 6 October 2006

[Ted Roche]

Lloyd Kvam of Venix Corporation presented the October meeting of the 
Dartmouth-Lake Sunapee Linux User Group, held in Corson Hall at 
Dartmouth College. Sixteen attendees were present.

Lloyd had a customer who had a serious problem develop: a Windows server 
they used, directly connected to the Internet, became infected with a 
worm and subsequent secondary infections. While technicians attempted to 
remove the malware from the machine, the company wanted to keep the 
machine online. Due to the critical nature of the tasks it was 
performing. it needed to continue to perform its main function, but 
needed communication (and further infections) to and from the internet 
curtailed as much as possible. Of course, this situation lead to a lot 
of armchair-quarterbacking on the part of attendees, but Lloyd pointed 
out that in the end it was the customer who determined the course of 
action, and Lloyd assisted them with it.

Lloyd used a LinkSys WRT54G he had spare in his office. He loaded it 
with the OpenWRT firmware. OpenWRT works differently from other 
firmwares we've seen demoed before. Rather than one fixed image loaded 
onto the router, OpenWRT provides a writable area in the router where 
updated or changed programs can be uploaded, and links moved from 
firmware to point at these updated files.

Lloyd had an excellent diagram (this one, I think:

http://upload.wikimedia.org/wikipedia/commons/0/0f/WRT54G_internal_architecture.png

that showed how the ports were wired together and how VLANs and bridges 
could be made to connect the various pieces. He then went to to 
demonstrate what sort of steps you would need to take from the 
command-line to create and configure separate VLANs and bridge them 
together. He also talked about the ebtables firewall and how rules could 
be written to allow nothing to and from the server but port 80 http 
traffic, while allowing other machines within the LAN to communicate 
with the machine on other ports.

An excellent presentation! Thanks to Lloyd for the presentation, to Bill 
McGonigle for arranging the facilities and moderation, and to Kjel 
Anderson for supplying the excellent munchies!

More info: http://www.openwrt.org
Lloyd: http://www.venix.com
DLSLUG/GNHLUG: http://www.dlslug.org and http://www.gnhlug.org