Router 1721 restart problem

Unanswered Question
Jul 16th, 2007


We have 1721 router.Today router restart automatically two times.I checked on router there is no log. can you tell what is the reason?

Thanks in Aedvance

I have this problem too.
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guruprasadr Mon, 07/16/2007 - 02:48

HI Upendra,

Please check the Configuration Register Status.

If possible post the "show tech-support" output file.

Best Regards,

Guru Prasad R

spremkumar Tue, 07/17/2007 - 20:35


As per the show version output the reload reason is due to power-on may be due to power fluctuations or powered down unknowingly by induviduals..


guruprasadr Tue, 07/17/2007 - 20:45

HI Upendra, [Pls RATE if HELPS]

Show output doesn't provide any specific root cause of Reload. It's just an normal boot progress. It may be because of Power Fluctuation / Somebody could have disturbted the Router.

I have some interesting INFO on seeing your show tech output:

Interface Serial1 (standby mode/down)

WARNING: This interface has had 4 interface resets.

This may occur if packets queued for transmission were not sent within several

seconds. This may be caused by a malfunctioning modem which is not supplying the transmit clock signal, or by a cable problem. If the IOS device notices that

the Carrier Detect signal of the serial interface is up, but the line protocol

is down, it periodically resets the interface in an effort to restart it. Interface resets may also occur when an interface is looped or shutdown.

TRY THIS: Use the 'clear counters Serial1' command to ensure current information

is being displayed. Check carrier transitions as well. If they are high while

interface resets are being registered, the problem is most likely a bad link

or CSU/DSU. Contact your service provider and swap faulty equipment as necessary.

Serial1 is standby mode, line protocol is down : LCP Closed

ERROR: LCP is in a 'Closed' state; meaning LCP has not been negotiated.

NOTE: The following steps utilize 'debug' commands.

TRY THIS: Troubleshoot LCP issues:

1. Use the commands: 'debug ppp negotiation' and 'debug ppp authentication'

2. Look for authentication failures or AUTH-NAK, correct as required.

3. If you see outbound LCP messages but no inbound LCP messages in the debugs,verify the remote device is configured for PPP on the respective interface.

4. If you see the inbound and outbound PPP messages in the debugs, review LCP negotiations for CONFNAK (Configure Negative Acknowledgement). If negotiated options are set to an unacceptable value, a CONFNAK is used to offer the requesting side a hint as to what an acceptable value would be. Occasionally, the two sides will not be able to agree on the options for a connection and will show repeated CONFREQ/CONFNAK or CONFREQ/CONFREJ. If you recognize this happening, review what LCP options are causing the issue and correct as necessary.


Best Regards,

Guru Prasad R

upendra07 Wed, 07/18/2007 - 01:31


I faced problem in today i saw on router only power led is up ethernet led is not blinking then i try to ping router gave "request time out" then i try to connect console cable router cold start automatically and working fine. I face same problem last 15 days . Any time router reboot automatically and any time router on but is not working. As per your info my vsat is working on serial 1 and lease is working on serial 0. I am not using bri0 port. when lease line goes down vsat up automatically.

Paolo Bevilacqua Wed, 07/18/2007 - 03:16

Even without evident output from "show commands", most "automatic resets" are caused by software crashes. Connect a PC to the console port and capture output - chances are that you will see something interesting when it crashes.

And if you do not, you know for sure it's a power or hardware issues.

guruprasadr Wed, 07/18/2007 - 03:59

HI Upendra,

As said in previous posts, your show output doesn't show any evidence / proof for "automatic resets".

This could be a Power disturbance / hardware issue as said by p.bevilacqua.


Best Regards,

Guru Prasad R


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