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Old 05-16-2009, 02:56 PM   #1
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Registered: May 2009
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Exposing a pTRTd TAP device to WAN

I am trying to use pTRTd to allow IPv6-4 translation. My current setup involves the following interfaces:
1. eth0 - This is the LAN port with 192.168.10.x (IPv4 only) network with a DHCP server and connected to a switch to allow multiple hosts to connect to the network.
2. eth1 - This is the WAN port with both an IPv4 and an IPv6 address created using a prefix advertised by an RADVD server.
3. tap0 - This is the TAP device created by pTRTd to allow translation. The prefix assigned to pTRTd is aaaa:bbbb:cccc:dddd::

From within my box, I can ping hosts on the network. I can also ping the hosts using IPv6 via

Now, I want my WAN devices to be able to do this as well. I am not an expert at Linux Networking. My gut feel is that I need to somehow accept packets coming into eth1 destined for the aaaa:bbbb:cccc:dddd network and route it to the tap0 interface (and vice versa). Can someone please help me out with this?

Old 07-01-2009, 06:16 PM   #2
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Registered: Feb 2007
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Same problem

I am having the same problem with ptrtd.
It works on the same box that it is run on...

Is it possible to set up a route to the machine running ptrtd
and access its functionality from a LAN?
eg: will it forward a range of IPv6 addresses on ethX to
IPv4 addresses on ethY ?

Old 07-03-2009, 10:20 AM   #3
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Registered: Feb 2007
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It does work...

In case anyone needs this in the future...
Here is a configuration that works for me.

Machine 1 (which runs ptrtd) RHEL5.2: 2.6.18-92.el5







sysctl -a | grep forward | grep ipv6
sudo /sbin/ipv6tables -L

sudo ip -6 addr add dev eth0 3ffe:ffff:fff:f::100/64

sudo ./ptrtd -p 3ffe:abcd:1234:9876::

Machine: 2 (client of ptrtd) FC4: 2.6.17-1.2139

sudo ip -6 addr add dev eth1 3ffe:ffff:fff:f::101/64

sudo ip -6 route add 3ffe:abcd:1234:9876/64 dev eth1
via 3ffe:ffff:fff:f::100

Testing (from machine 2):

ping6 3ffe:abcd:1234:9876::
ssh 3ffe:abcd:1234:9876::
telnet 3ffe:abcd:1234:9876:: 80
GET / HTTP/1.0<cr>
Old 08-19-2009, 01:26 PM   #4
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Registered: Feb 2007
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Fix for ptrtd throughput bug

FYI: In case anyone is using ptrtd...

There is bug in ptrtd that causes it to fail under
heavy traffic conditions. I reported it to the author
of ptrtd and he reports that he is no longer supporting
it. I have attached a patch file provided by J.Koenig
of He also has an updated version of ptrtd

Attached Files
File Type: txt ptrtd-short-write-fix.txt (1.7 KB, 3 views)
Old 06-18-2010, 05:17 PM   #5
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Registered: Feb 2007
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Latest ptrtd

The latest ptrtd is archived at:



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