Hi!
I've been trying to see what was making the conection of two 2.2.14 linux
machines trough plip imposible, and this are the things that I saw that
have become lost in the plip driver compared to 2.0.38:
The old kernels used to accept any package on a plip device no mather
wich destination mac it had, while 2.2.14 only accepts its mac and the
broadcast mac.
Also 2.2.14 sets the destination mac on the plip device to 0:0:0:0:0:0 the
first time and afterwards it sets it to its own mac, thus h_source and
h_dest are the same. The old 2.0.38 can guess remote mac address without
any arp requests, thus setting the h_dest correctly even if configured
for NOARP (default PLIP setting).
I'll put here a couple of examples that show all this:
First example: two 2.2.14 machines (fc:fc:c0:a8:1:f3 and fc:fc:c0:a8:1:3)
linked through PLIP.
The first package is a normal ping, wich doesn't work because of the
destination mac being the local mac instead of the remote, then all the
others are simulated packages, they are however exactly like the ping but
changing the destination mac address, as you can see, it only replies to
it's own mac or the broadcast.
tcpdump: listening on plip0
22:39:45.697286 fc:fc:c0:a8:1:f3 fc:fc:c0:a8:1:f3 0800 98: 192.168.1.243 >
192.168.1.3: icmp: echo request
22:39:49.910218 fc:fc:c0:a8:1:f3 ff:ff:ff:ff:ff:ff 0800 98: 192.168.1.243 >
192.168.1.3: icmp: echo request
22:39:49.918798 fc:fc:c0:a8:1:3 fc:fc:c0:a8:1:3 0800 98: 192.168.1.3 >
192.168.1.243: icmp: echo reply
22:39:54.344615 fc:fc:c0:a8:1:f3 fc:fc:c0:a8:1:3 0800 98: 192.168.1.243 >
192.168.1.3: icmp: echo request
22:39:54.358937 fc:fc:c0:a8:1:3 fc:fc:c0:a8:1:3 0800 98: 192.168.1.3 >
192.168.1.243: icmp: echo reply
22:39:57.262864 fc:fc:c0:a8:1:f3 fc:fc:c0:a8:1:5 0800 98: 192.168.1.243 >
192.168.1.3: icmp: echo request
Second example: A 2.2.14 ARP pinging a 2.0.38 NOARP (same macs as above):
As you can see 2.0.38 replies even though the destination mac is not its
address and also it sets the replying address ok, even though it is set to
NOARP and its arp tables don't show the address of 192.168.1.243.
tcpdump: listening on plip0
23:05:09.305700 fc:fc:c0:a8:1:f3 fc:fc:c0:a8:1:f3 0800 98: 192.168.1.243 >
192.168.1.3: icmp: echo request
23:05:09.309992 fc:fc:c0:a8:1:3 fc:fc:c0:a8:1:f3 0800 98: 192.168.1.3 >
192.168.1.243: icmp: echo reply
Well, hope this helps somebody out there with more time find a solution
for this.
Regards!
Manty/BestiaTester -> http://manty.i.am
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