[lwip-users] [lwip] Bahadir Balban Question

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Hello Bahadir!
I'm also working on lwip under linux. I had the same problem than you. Tapif is 
a virtual device that "expands" your ip addresses set with another
one. When 
you successfuly install tapif (/dev/tap0 - 1? or /dev/net/tun), after the calls 
Lwip do (such as netif_add(gw,ip,device...)) you can run ifconfig and see that 
you have another device more than lo and eth0 called tap0 that has it's own Ip 
adress, gateway etc. So ip adress attached on tapif will become one of your 
local adresses. It olny works for local tests (pings, telnets, etc..) because 
it is a virtual device. 
Kernels 2.4x seem to cause problems installing tapif. Some mails about this 
question have been sent to lwip discussion list but I solved that problem.
The way I succesfully installed tapif was following the instructions I read in 
a manual I found in internet. Your kernel must be compiled with TAP/TUN 
support, but it doesn't work at all. You must create the device by hand with 
the command mknod, but I don't remember wich minor an major numbers are 
correct. Search internet and you'll find some help in this way. 

Testing LWIP is a problem I actually have. If you succeed installing Lwip you 
can ping from your computer (not a remote one) LWIP stack, or probe the http 
daemon by adding in a explorer http://ip_adress, or probe "telnet ip 7" to test 
udpecho program. The Problem I have is how to test LWIP just using loop 
interface. I think loopif must be attached on a real device, such as eth0 or 
tap0 (it is virtual but real :)

Send your questions to LWIP community, all of them will be interested (if they 
weren't, no answer would be sent, isn't it??).
Anyway, we're working on the same platform (linux) so you can redirect your 
questions to me. If I can help you I would be pleased doing it. 

CIAO.


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