I noticed in the running config I don't see the no synchronization command under the BGP section. Is this a default command so I won't see it unless I change it?

Hardware / software

  • Cisco 1921

  • c1900-universalk9-mz.SPA.151-4.M5

1 Answer 1


In most modern versions of IOS (since 12.2(8)T - thanks @ytti) BGP synchronization is disabled by default (and shown in the running config as such, ie no synchronization shows up in show run when you turn on BGP). As to which IOS version they decided to make it a "hidden default", I'm not entirely too sure, but you should be able to do:

show running-config all


show running-config full

To get the router to show the entirety of the running config, including the defaults which are normally hidden. Look for no synchronization in there.

  • 5
    It's been disabled since 12.2(8)T so many years now, ref: cisco.com/en/US/tech/tk365/…
    – ytti
    Commented Jun 3, 2013 at 19:45
  • Yeah, I figured it had been a long time, I just didn't remember which release they decided to make "no synchronization" the default, which would make sense. As to what version they decided to make the default "hidden" in, I'm not sure. Commented Jun 3, 2013 at 19:47

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