Messages in this thread | | | Date | Wed, 3 Feb 1999 13:59:07 -0600 (CST) | From | "Brynn D. Rogers" <> | Subject | how can one bypass the automatic loopback? |
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I have 5 ethernet ports in my computer and I am debugging ethernet drivers.
Two ports are looped back externally with crossed 10baseT wire. No matter what I have tried I am unable send a ping (that will be responded too) through that cable.
eth3 Link encap:Ethernet HWaddr 00:00:BC:11:19:FC inet addr:192.168.2.2 Bcast:192.168.2.255 Mask:255.255.255.255
eth4 Link encap:Ethernet HWaddr 00:40:95:D2:C2:85 inet addr:192.168.3.1 Bcast:192.168.2.255 Mask:255.255.255.255
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.3.1 0.0.0.0 255.255.255.255 UH 0 0 0 eth3 192.168.2.2 0.0.0.0 255.255.255.255 UH 0 0 0 eth4
If I ping 192.168.2.2 the kernel 'knows' that we are already at the destination and short circuits that packet before it ever gets down to the hardware. I get about .2 ms ping time and ifconfig reveals that no packets were transmitted or received by the hardware.
Is there any way around this?
P.S. I know that I can add a route to a bogus host on eth3 and ping it, then I will at least see the packets going on the wire, but I cannot ping myself by way of this external loopback cable.
Brynn Brynn Rogers brynn@tiny.net http://www.visi.com/~brynn to see my triplets!
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