[sdnog] Terminal Server

[Nishal Goburdhan]

Hiba Eltigani wrote:
> Salam SdNOG
>       We have some equipments in distant area around 8 hours (plane
> trip) from Khartoum. We are using 3600 series cisco router as terminal
> server to insure console connectivity. We use SSH connection to access
> the server, then we access any device terminal through reverse
> telnet.But in 70% of the time, when we disconnect from that device; we
> will loose the connection to the server itself and we have to initiate
> new session multiple times to reconnect.
> So, my questions are:
> - what can be the cause for that?


as a quick guess, i would say that the "break" or "disconnect" sequence 
that you're sending to the end-host is being interpreted by the console 
server as disconnect too.  so, perhaps the starting place would be to say:
* what break/disconnect signal am i sending ?
* what -should- i be sending instead ?

one trick that you can use quite easily on a cisco is to "go back" or 
suspend a session, and then, issue a disconnect.  the key sequence, for 
that is (or used to be)  ctrl+shift+6+x

ie:
* ssh to console server
* connect to device's console
* issue key-sequence to return you to console-server (but stay logged 
into device)
* issue key-sequence to disconnect you from device

the other thing to consider is that your terminal client should also 
support this as well.


> - is there any recommendations to enhance connection reliability to
> insure it is up all the time?

i am not sure i understand this;  you have a remote console server, 
right?   that's physically connected to the console of different 
devices, right?    it should be reliable ?  :-)

what you might find is that people are still logged into the console, 
thus locking them out.   using something like RANCID   *cough*  you can 
very easily issue commands like "show user" on the console once a day, 
to make sure there are no idle consoles running, and thus the 
connections should be reliable.


> - is there any comparable solutions that give the same functionality?

in addition to what's been said, people write good things about 
opengear.  a friend i know has a freeBSD box with a USB hub, and 
usb<->serial adaptors  :-)


--n.