iptables, bridging and inside-/outside-issue
After reading through the article series by Mick Bauer regarding transparent firewalls I got a bit inspired to try for myself.
I've installed ubuntu onto a machine with 3 network interfaces, and bridged these three interfaces to one common bridge.
I've copied the iptables-script from part V in the series, but re-written it due to the fact that I in my installation will be unable to sort traffic based on ip.
I will not know which addresses will be used on either side of the firewall, so I'll have to sort my traffic on some other variable.
I was thinking that I could sort the traffic based on PHYSIN and PHYSOUT in iptables, but -i and -o does not seem to do that.
As an example I've created the following rule:
iptables -A FORWARD -i eth1 -o eth0 -p tcp --dport 80 -j ACCEPT
But I still get the following in my kernel log:
floyd kernel: [269519.979985] Dropped by default (FORWARD): IN=br0 OUT=br0 PHYSIN=eth1 PHYSOUT=eth0 SRC=10.0.0.113 DST=18.104.22.168 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=31771 DF PROTO=TCP SPT=35727 DPT=80 WINDOW=5840 RES=0x00 SYN URGP=0
Which as far as I can figure should be allowed by the rule.
What can I do to sort the traffic based on the physical interface?
Fast/Flexible Linux OS Recovery
On Demand Now
In this live one-hour webinar, learn how to enhance your existing backup strategies for complete disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible full-system recovery solution for UNIX and Linux systems.
Join Linux Journal's Shawn Powers and David Huffman, President/CEO, Storix, Inc.
Free to Linux Journal readers.Register Now!
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- Profiles and RC Files
- Astronomy for KDE
- Understanding Ceph and Its Place in the Market
- Maru OS Brings Debian to Your Phone
- OpenSwitch Finds a New Home
- Git 2.9 Released
- SoftMaker FreeOffice
- What's Our Next Fight?
- The Giant Zero, Part 0.x
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide