SSH stops working
 

Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
12.4.1a, but if I restarts the router then it will work fine again.

When this problem happens, all other functions of the router seems
working fine. Workstations still be able to access the Internet, VPN
Client still be able to connect to the router ... only I can not ssh to
the router.

Any idea where I can look at ?

Thanks,

DT

Re: SSH stops working
 

Hi DT,

You may wish to investigate the Cisco Feature Navigator:

http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp

As well as Cisco's Configuring Secure Shell on Routers and Switches
Running Cisco IOS

http://www.cisco.com/warp/public/707/ssh.shtml

Sincerely,

Brad Reese
BradReese.Com Cisco Repair Service Experts
1293 Hendersonville Road, Suite 17
Asheville, North Carolina USA 28803
Toll Free: 877-549-2680
International: 828-277-7272
Website: http://www.bradreese.com/cisco-big-iron-repair.htm

Re: SSH stops working
 

dt1649651@yahoo.com wrote:
> Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
> 12.4.1a, but if I restarts the router then it will work fine again.
>
> When this problem happens, all other functions of the router seems
> working fine. Workstations still be able to access the Internet, VPN
> Client still be able to connect to the router ... only I can not ssh to
> the router.

Which kind of problem (connection timeout, connection refused or simply the client exits without any error messages)
Have you perhaps changed RSA keys? After having changed them it will never accept new connections.
It happened to me with 12.4.1

HTH Alex.

Re: SSH stops working
 

www.BradReese.Com wrote:
> Hi DT,
>
> You may wish to investigate the Cisco Feature Navigator:
>
> http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp
>
> As well as Cisco's Configuring Secure Shell on Routers and Switches
> Running Cisco IOS
>
> http://www.cisco.com/warp/public/707/ssh.shtml
>
Hi Brad, thanks for your reply. Yes I did use those URL when I set up
SSH on my router. I may have to read it again.

What I do not understand is after I restart the router, it works fine
again.

DT

Re: SSH stops working
 

AM wrote:
> dt1649651@yahoo.com wrote:
> > Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
> > 12.4.1a, but if I restarts the router then it will work fine again.
> >
> > When this problem happens, all other functions of the router seems
> > working fine. Workstations still be able to access the Internet, VPN
> > Client still be able to connect to the router ... only I can not ssh to
> > the router.
>
> Which kind of problem (connection timeout, connection refused or simply the client exits without any error messages)
> Have you perhaps changed RSA keys? After having changed them it will never accept new connections.
> It happened to me with 12.4.1
>

Hi Alex, thanks for your reply.
I get the error "Connection refused.". No I do not change the key.
Currently my temporary fix is to restart the router ( if it happens
during the weekend ) or to use my Linux box with the serial cable to
the console.

DT

Re: SSH stops working
 

dt1649651@yahoo.com wrote:
> AM wrote:
>
>>dt1649651@yahoo.com wrote:
>>
>>>Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
>>>12.4.1a, but if I restarts the router then it will work fine again.
>>>
>>>When this problem happens, all other functions of the router seems
>>>working fine. Workstations still be able to access the Internet, VPN
>>>Client still be able to connect to the router ... only I can not ssh to
>>>the router.
>>
>>Which kind of problem (connection timeout, connection refused or simply the client exits without any error messages)
>>Have you perhaps changed RSA keys? After having changed them it will never accept new connections.
>>It happened to me with 12.4.1
>>
>
>
> Hi Alex, thanks for your reply.
> I get the error "Connection refused.". No I do not change the key.
> Currently my temporary fix is to restart the router ( if it happens
> during the weekend ) or to use my Linux box with the serial cable to
> the console.
>
> DT
>

Since you're on the console you could do some debug to find out what's
going on.

Re: SSH stops working
 

polio wrote:
> dt1649651@yahoo.com wrote:
> > AM wrote:
> >
> >>dt1649651@yahoo.com wrote:
> >>
> >>>Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
> >>>12.4.1a, but if I restarts the router then it will work fine again.
> >>>
> >>>When this problem happens, all other functions of the router seems
> >>>working fine. Workstations still be able to access the Internet, VPN
> >>>Client still be able to connect to the router ... only I can not ssh to
> >>>the router.
> >>
> >>Which kind of problem (connection timeout, connection refused or simply the client exits without any error messages)
> >>Have you perhaps changed RSA keys? After having changed them it will never accept new connections.
> >>It happened to me with 12.4.1
> >>
> >
> >
> > Hi Alex, thanks for your reply.
> > I get the error "Connection refused.". No I do not change the key.
> > Currently my temporary fix is to restart the router ( if it happens
> > during the weekend ) or to use my Linux box with the serial cable to
> > the console.
> >
> > DT
> >
>
> Since you're on the console you could do some debug to find out what's
> going on.

Hi Polio, thanks for your reply.

Yes, that's what I am waiting for at this time :) because it only
happens sometimes, and while waiting for it to happen again, I would
like to know if anybody experiences it. :)

DT

Re: SSH stops working
 

In article <1121663685.931446.174560@o13g2000cwo.googlegroups .com>,
"dt1649651@yahoo.com" <dt1649651@yahoo.com> wrote:

> Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
> 12.4.1a, but if I restarts the router then it will work fine again.
>
> When this problem happens, all other functions of the router seems
> working fine. Workstations still be able to access the Internet, VPN
> Client still be able to connect to the router ... only I can not ssh to
> the router.
>
> Any idea where I can look at ?

I used to see this happen when the router runs out of memory.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Re: SSH stops working
 

dt1649651@yahoo.com wrote:

> Sometimes I cannot ssh to my router, a c2811 with advanced enterprise
> 12.4.1a, but if I restarts the router then it will work fine again.
>
While it happens please have a look to the number of connections opened by the router for NAT ("sh ip nat tra") in case use

ip nat translation max-entries <# of translations>


Alex.

Re: SSH stops working
 

it seems to be a ARP issue. if it occurs again just clear the ARP on
your oruter and your ISP router. See if it works. After that.
Rebooting the router clears all the tables that is the only diference.
so may be you could clear the nat table as well.