[c-nsp] Weird telnet problem on 7204VXR

[Dennis Peng]

Mike Bacher [isp-list at tulsaconnect.com] wrote:
> 
> 
> Dennis Peng wrote:
> >It's a bug. If you do a "show line vty X", you should see "Ctrl-C
> >Enabled" under the "Status" for the line. This causes the Username
> >prompt to timeout immediately when you try to use that line. It should
> >only effect one of the vty lines (although it may be vty 0 which is
> >the worst), but if you telnet back to the router right away, you
> >should get another line which should not have this problem. There is
> >no way to clear the condition, short of a reload.
> 
> Ok, I tried two simultaneous telnet's and got in on one.  Also:
> 
> dsl1#show line vty 1
>    Tty Typ     Tx/Rx    A Modem  Roty AccO AccI   Uses   Noise  Overruns   
>    Int
>      3 VTY              -    -      -    -    -     44       0     0/0      
>      -
> 
> Line 3, Location: "", Type: ""
> Length: 24 lines, Width: 80 columns
> Baud rate (TX/RX) is 9600/9600
> Status: Ready, No Exit Banner, Control-c Typed, Ctrl-c Enabled
> Capabilities: none
> Modem state: Ready
> 
> So, it looks like we are being bitten with the ctrl-c "bug" all of a sudden 
> (this hasn't been a problem until recently, and its been running for 
> several months with this IOS).  Is this problem caused by the previous 
> person that connected to that vty using Ctrl-C at some point?

Typing ctrl-c by itself won't cause the problem. You would have to use
a command which enabled ctr-c (to allow you to abort the command), but
didn't disable it correctly (like the atm ping command in older
versions).

> Is there a way just to disable the affected vty line or some other 
> workaround? This bug is hosing our ability to auto-provision DSL customers..

You can disable telnet as an allowed "transport input" so that it is
not used for telnet connections until you have the opportunity to
reload the router.

Dennis

> -- 
> 
> -----------------------------------------
> Mike Bacher / isp-list at tulsaconnect.com
> TCIS - TulsaConnect Internet Services
> Phone: 918-584-1100x110 Fax: 918-582-5776
> -----------------------------------------