Where is logging for interface negotiation history?

Question

Hey all, 
 I googled it and I searched the forums here - but like all valuable tech nuggets I believe the answer is hidden in the nix/CLI which I'm pretty sure 99.999% of the world doesn't know how to leverage. 
 Being in the 99.999% - I'm hoping someone can tell me. 
 A customer is stating that he has an interface flapping (WAN) due to negotiation issues - but I can't confirm or deny. 
 Please advise.

Keyur · Accepted Answer

Hi John Woodall 
 Please login to advanced shell execute below given command. cd /log 
 tail -f applog.log or cat applog.log | grep "interface=port2" 
 Please share the output to check

lferrara · Answer

John, 
 check in the applog.log if you have interface up and down. From advanced shell type: 
 cat applog.log | grep "Interface=Port2" 
 Port2 is my WAN port. Adapt it in your case.