Bridging Mac OSX to Real Networks… part 1

Ok, i know that people are probably going to say “this is documented” – but it’s not really. At least not REALLY well. Before i start i want to list the aims of this little project detailing the issues i get as i go along:
1) I want to be able to bridge my Dynamips instances to a real network
2) i want to be able to use the breakout method to enable my routers to connect to 4 switches (hopefully 2 x 3560, 2 x 3550) and possibly i will need an 8-pc 3560 as the actual breakout switch.
3) I want to be able to finish this before i go grey!

I was just reading a post (about my 50th one today – seriously!), that someone took 6 months to get his tuntaposx installation working. 6 MONTHS!! I’ll be crying if this takes me longer than 6 days.
Below is a list of the most useful posts so far that i’ve found:

http://www.bitsontheline.com/certifications/gns3-virtualbox-osx-1/
http://7200emu.hacki.at/viewtopic.php?t=3760
http://7200emu.hacki.at/viewtopic.php?t=7540
http://7200emu.hacki.at/viewtopic.php?t=6134&sid=7d390288e37c248f372926ffa4db890a
http://www.blindhog.net/how-to-connect-gns3-to-internet-in-macosx/

ok, what’s the first step? Many of these posts are detailing that running Dynamips plays a big part, so let’s do that first. So what did i do again for that? Oh yeah,
Open any folder on your Desktop > Applications > Utilities > Directory Utility > Edit (in the top toolbar) > Enable Root User (you may have to click the padlock and enter details – must be an admin to do this!)

To check this:
Open any folder on your Desktop > Applications > Utilities > Activity monitor

Yes!! I can see that Dynamips is listed under ROOT.

I then went to http://tuntaposx.sourceforge.net/ and downloaded the latest version AND also the legacy version for my OS. This is because i tried to install the latest one but it wouldn’t install. So i downloaded the 36K, 88K and 636K versions.

Here’s an exert of my post on Hacki Forum:
OK, it looks as if i’ve made some real progress here, Alhamdu lillah. By following the blog on:

http://www.blindhog.net/how-to-connect-gns3-to-internet-in-macosx/

I’ve decided to install the tuntaposx and i installed it (had to do it twice because it wouldn’t recognize the 1st time around).
I then followed some instructions and used:
“cd/dev” followed by “ls” or i suppose you could try “ls /dev”. I got to see the “tun” and “tap” interfaces.
Then i tried to assign an ip address to the tap0 interface:
“sudo ifconfig tap0 10.100.100.100 netmask 255.255.255.0″ and i got:
ifconfig: interface tap0 does not exist

The last comment in the post states:
“…I made a .net file the same as above, then did ifconfig -l and did not see the tap0 int.
Then I started my .net file (not even using the sudo commands as above). After the gns3 .net file loaded – I saw a connection from C0 to R1 for the first time ever!”

So i decided to ignore the fact that i wasn’t seeing the tap interface and go ahead. Here’s my simple .net file:
[localhost]

[[7200]]
image = /applications/cisco-images/C7200-AD.BIN
# On Linux / Unix use forward slashes:
# image = /opt/7200-images/c7200-jk9o3s-mz.124-7a.image

ram = 160
npe = npe-400
idlepc = 0x607919a8
mmap = true
ghostios = true
sparsmem = true

[[ROUTER R1]]

F0/0 = nio_tap:/dev/tap0                        <– this took MANY tries to get right!!
model = 7200

and once i started up Dynamips (that’s what i’m using NOT GNS!!) and assigned an address in the same subnet as the tap0 interface i got:

Router(config)#do ping 10.100.100.255 rep 20

Type escape sequence to abort.
Sending 20, 100-byte ICMP Echos to 10.100.100.255, timeout is 2 seconds:

Reply to request 0 from 10.100.100.100, 8 ms
Reply to request 1 from 10.100.100.100, 16 ms
Reply to request 2 from 10.100.100.100, 12 ms
Reply to request 3 from 10.100.100.100, 4 ms
Reply to request 4 from 10.100.100.100, 16 ms
Reply to request 5 from 10.100.100.100, 28 ms

But it was taking about 10 secs for each ping reply (even though it stated 8 ms). I left it for a while and the console timed out. When i logged back in i get:

Router#ping 10.100.100.100

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.100.100.100, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/12/28 ms

The TAP0 interface is replying!! That’s EXCELLENT. Alhamdu Lillah.

When i type in “ifconfig” under a new terminal shell window i see:

tap0: flags=8843 mtu 1500
inet 10.100.100.100 netmask 0xffffff00 broadcast 10.100.100.255
ether b2:36:73:6b:e2:aa
open (pid 199)

This is the tap interface with the assigned ip address i gave it. I’m getting genuinely excited here

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