I’ve come into possession of a ASYNC Network Module for a Cisco router. I plan on using it for Cisco lab stuff(s) when I get back into CCIE mode but I thought I’d pop it into an old 2600 and make sure it was working. I’m glad I kept the two 2610’s that I had. Perfect (and cheap) chassis to use the NM in. So here we go, pretty basic stuff…
The basics, name and IP
Router>en
Router#config t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#hostname TAD_ROUTER
TAD_ROUTER(config)#int et0/0
TAD_ROUTER(config-if)#ip address 10.20.30.8 255.255.255.0
TAD_ROUTER(config-if)#exit
Now, lets make sure that the router picked up on the ASYNC module, take a look at the output of the ‘show line’ command…
TAD_ROUTER#show line
Tty Typ Tx/Rx A Modem Roty AccO AccI Uses Noise Overruns Int
* 0 CTY - - - - - 0 0 0/0 –
33 TTY 9600/9600 - - - - - 3 12 0/0 –
34 TTY 9600/9600 - - - - - 0 0 0/0 –
35 TTY 9600/9600 - - - - - 0 0 0/0 –
36 TTY 9600/9600 - - - - - 0 0 0/0 –
37 TTY 9600/9600 - - - - - 0 0 0/0 –
38 TTY 9600/9600 - - - - - 0 0 0/0 –
39 TTY 9600/9600 - - - - - 0 0 0/0 –
40 TTY 9600/9600 - - - - - 0 0 0/0 –
41 TTY 9600/9600 - - - - - 0 0 0/0 –
42 TTY 9600/9600 - - - - - 0 0 0/0 –
43 TTY 9600/9600 - - - - - 0 0 0/0 –
44 TTY 9600/9600 - - - - - 0 0 0/0 –
45 TTY 9600/9600 - - - - - 0 0 0/0 –
46 TTY 9600/9600 - - - - - 0 0 0/0 –
47 TTY 9600/9600 - - - - - 0 0 0/0 –
48 TTY 9600/9600 - - - - - 0 0 0/0 –
49 TTY 9600/9600 - - - - - 0 0 0/0 –
50 TTY 9600/9600 - - - - - 0 0 0/0 –
51 TTY 9600/9600 - - - - - 0 0 0/0 –
52 TTY 9600/9600 - - - - - 0 0 0/0 –
53 TTY 9600/9600 - - - - - 0 0 0/0 –
54 TTY 9600/9600 - - - - - 0 0 0/0 –
55 TTY 9600/9600 - - - - - 0 0 0/0 –
56 TTY 9600/9600 - - - - - 0 0 0/0 –
57 TTY 9600/9600 - - - - - 0 0 0/0 –
58 TTY 9600/9600 - - - - - 0 0 0/0 –
59 TTY 9600/9600 - - - - - 0 0 0/0 –
60 TTY 9600/9600 - - - - - 0 0 0/0 –
61 TTY 9600/9600 - - - - - 0 0 0/0 –
62 TTY 9600/9600 - - - - - 0 0 0/0 –
63 TTY 9600/9600 - - - - - 0 0 0/0 –
64 TTY 9600/9600 - - - - - 0 0 0/0 –
65 AUX 9600/9600 - - - - - 0 0 0/0 –
66 VTY - - - - - 0 0 0/0 –
67 VTY - - - - - 0 0 0/0 –
68 VTY - - - - - 0 0 0/0 –
69 VTY - - - - - 0 0 0/0 –
70 VTY - - - - - 0 0 0/0 –
Line(s) not in async mode -or- with no hardware support:
1-32
As you can see, it’s determined that we have an additional 32 TTY lines. So let’s configure those for reverse telnet….
TAD_ROUTER#
TAD_ROUTER(config)#line 33 64
TAD_ROUTER(config-line)#transport input all
TAD_ROUTER(config-line)#transport output all
TAD_ROUTER(config-line)#end
Be good and write your config…
TAD_ROUTER#write
Building configuration…
[OK]
TAD_ROUTER#
Now, at this point, it’s actually all set. I’m not configuring any authentication since this is a lab box, but if I wanted to I could configure login with the ‘login’ command underneath the line configuration. Now a quick test…
TAD_ROUTER#telnet 10.20.30.8 2033
Trying 10.20.30.8, 2033 … Open
virtual>
virtual>
Virtual is the name of a 3750 I have the console port connected to. So to disconnect, simply press Ctrl-Shift+6. Then hit the ‘X’ key. This kicks you back to the TAD router where you can issue the disconnect command…
TAD_ROUTER#disconnect
Closing connection to 10.20.30.8 [confirm]
TAD_ROUTER#
Now, you can also access this console port by just telnetting from anywhere on the network to 10.20.30.8 2033. Are you asking yourself where the 20 came from in front on line 33? For some reason (I actually don’t know why) the reverse telnet lines on a Cisco router start with 20XX. That’s just how it is 🙂
Enjoy!