I stumbled upon this while doing Person VUE Test Prep for CCNA and I came up with a question that google wasn't that helpful for. (This is just for curiosity, so a basic answer will do, but for others feel free to give details.)

enter image description here In the above output from the command what does PADISNT mean/Stand for? Like I said a basic google didn't find much. http://rs.ccnacookbook.com/BookNotes/15D_PPPoE_Troubleshooting.pdf This website says if you see it check if Ethernet's shut down.

wikipedia says PADI = PPPoE Active Discovery Initiation

but that's all I could find about it. When I see an acronym I like to know what it means is all.

2 Answers 2


A PPPoE session is always initiated by the PPPoE client. It will attempt to re-establish the connection if the session has a time-out or is disconnected. the following four steps occure during the Discovery stage:

The client broadcasts a PPPoE Active Discovery Initiation (PADI) packet. If an access concentrator receives a PADI that it can serve, it replies by sending a PPPoE Active Discovery Offer (PADO) packet to the client.

Because the PADI was broadcast, the host may receive more than one PADO packet. The host looks through the PADO packets it receives and chooses one. The choice can be based on the access concentrator name or on the services offered. The host then sends a single PPPoE Active Discovery Request (PADR) packet to the access concentrator that it has chosen.

The access concentrator responds to the PADR by sending a PPPoE Active Discovery Session-confirmation (PADS) packet. At this point a virtual access interface is created that will then negotiate PPP, and the PPPoE session will run on this virtual access.

There is another packet type which can be sent to indicate that the PPPoE session has been terminated. Either the Client or the Access Concentrator can send the PPPoE Active Discovery Terminate (PADT) packet at any time after the session is established. When a PADT packet is received, no further PPP traffic is allowed to be sent using that session. A PPP peer should use the PPP protocol itself to bring down a PPPoE session, but the PADT may be used when PPP can not be used.

SNT after PADI just means Ethernet is admin shutdown.

  • Thanks for the extra information. I know know that PADISNT means: PPPoE admin shutdown. And that it probably stands for something along the lines of: PPPoE Active Discovery Initiate Session Network Termination or something, close enough given the scarcity of information on this particular subject.
    – neoakris
    Jul 12, 2017 at 16:30

On a point to point link, I had not applied the pppoe to the interface yet on the server side and the client "show pppoe sessions" command showed the PADISNT state for the interface.

So connection wise, it means the Dialer interface is up but the PPPoE session is down.

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