I'm networking beginner

I have a remote site without any servers and a Cisco 861 that has and IPsec VPN tunnel back to the main office. I get an alert that it's offline via a ping test. Yesterday this happened and I just power cycled the unit and they were back up in a few minutes.

It happened again this morning (approx. 15 hours later) so I investigated further:

  1. LEDs look ok (WAN is blinking a bit)
  2. Can't ping inside interface via the LAN
  3. Unable to connect to console
  4. Power cycled
  5. Console connection displays the boot process and everything is back to normal after it boots up.

If I can't even connect to the console to review where should I start? I have a desktop PC that could collect syslog info but I wouldn't think that would be helpful given the problem accessing the console. There are only 10 users connecting to the router.

EDIT: include show version

sho ver
Cisco IOS Software, C860 Software (C860-UNIVERSALK9-M), Version 15.0(1)M5, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Wed 23-Feb-11 19:44 by prod_rel_team

ROM: System Bootstrap, Version 12.4(22r)YB5, RELEASE SOFTWARE (fc1)

uptime is 39 minutes
System returned to ROM by power-on
System image file is "flash:c860-universalk9-mz.150-1.M5.bin"
Last reload type: Normal Reload

Cisco 861 (MPC8300) processor (revision 1.0) with 236544K/25600K bytes of memory.
Processor board ID FTX151603YG

5 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
256K bytes of non-volatile configuration memory.
126000K bytes of ATA CompactFlash (Read/Write)


  • When you say that you "can't connect to the console", what specific means are you trying? Do you actually have a serial cable plugged into the CONSOLE port with the other end plugged into a laptop? A cable between the CONSOLE port and a serial server? SSH? Commented Aug 8, 2013 at 18:56
  • I mean a serial cable plugged into the CONSOLE port with the other end plugged into a laptop. It works when I reboot the unit after the crash.
    – PHLiGHT
    Commented Aug 8, 2013 at 20:34

3 Answers 3


I haven't understood if you are or are not able to access the console when the device is not working. If you cannot access the console, it looks bad. Adding a syslog server is a very good idea, the device might send something prior to crashing.

Check if the IOS you are running is fine or deprecated due to problems and upgrade accordingly.

Usually such behavior is a good reason to open a tac case at cisco, provided you still have some support contract.

  • @PHLiGHT, should also check with administrators of other end of the VPN tunnel, their router may have useful logs too. Commented Aug 8, 2013 at 14:01
  • 1
    When the device isn't working I can't access the console. When it is I can.
    – PHLiGHT
    Commented Aug 8, 2013 at 14:01

Most of the good advice has been covered, but also: There's an outside chance that a debug command could have been responsible. They're not preserved between reboots, but if some debug option is getting set (via SNMP, some newbie admin like young @chrylis), it can linger until triggered and then crush the router's entire processing capability so hard it'll never come back.


Do a show version, it might tell you why box froze. I'd also check the IOS version to see if there is a more recent version from cisco. Also have a look at the syslog, it might give you information on why the router died.

Edit: - Much newer IOS available from Cisco - they're upto 15.3, and that version has been pulled from the download which could suggest bugs with it.

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