Talk:Layer 2 Tunneling Protocol

Undated anonymous question
is it just me or did l2tpd.org vanish?

Yes, the company hosting that domain lost interest and a domain hijacker took it. Check out the news at https://sourceforge.net/projects/l2tpd/

I just noticed that. Those hijackers are really completely sickening. :-( Anyway, I just noticed this page mentions that PPTP is a Microsoft technology, while the PPTP Wikipedia page says it's invented by Cisco and licenses by Microsoft. What's true?

L2TP/IPSec
Thought that a section on these would be useful. Unfortunately, I forgot to sign in, so it's not attributed to me. If you have questions, my username follows. If anyone has a nice picture of the full encapsulation (IP-ESP-UDP-PPP-L2TP-Private IP-TCP/UDP-Data), it would help understanding. Scorpiuss 17:13, 8 February 2006 (UTC)


 * Doesn't PPP follow L2TP? Iglam 01:36, 18 October 2007 (UTC)

Be sure to consider MTU when implementing L2TP. Doesn't sound too informative, kind of like "be sure to consider the steering wheel while driving a car". Should be explained, or removed.

The correct name is L2TP/IPsec, not L2TP/IPSec (see RFC).

L2TP/IP ?
Is it common to establish L2TP-tunnel over a completely insecure channel, i. e. IP without IPsec over it? I just wonder whether SOHO routers really implement IPsec when connecting to ISP in L2TP mode. At least, they don't support MPPE encryption for PPPoE and PPTP tunnels (for performance reasons, I suppose), so it's very doubtful that they will do IPsec encryption, even the most simple one, 3DES. Moreover, the throughput in L2TP mode can be in fact higher than in PPPoE / PPTP modes, which can be a direct indication of cryptographical absence. 213.234.235.82 (talk) 13:20, 12 February 2009 (UTC)

Section on Windows implementation is just wrong
The section on the Windows L2TP implementation seems to be a reworked copy of the "IPsec without L2TP" section of this document here: http://www.jacco2.dds.nl/networking/vista-openswan.html. As such it is describing raw IpSec-RA or IpSec-L2L, (not "L2TP without IPsec") which has absolutely nothing to do, of course, with L2TP. (140.232.0.70 (talk) 14:33, 23 September 2010 (UTC))

What is the purpose of this section anyway? I suggest we remove this section. — Preceding unsigned comment added by 2A00:865:A88E:A820:0:0:0:19E (talk) 10:31, 21 April 2015 (UTC)

Agreed! IMHO, I agree with removal or rewrite. It seems pointless, especially as Windows Server has supported L2TP without all the shenanigans apparently required or hinted at by this article. It's just FUD. Seems like more of a diatribe over a getting a narrow L2TP server to work with Windows Vista, without all the other support structure of L2TP in the real world (IPSEC). Not sure it needs to be here, very few people would do this.

Jgwinner (talk) 21:00, 2 November 2015 (UTC)

Renaming page for better accuracy
I am planning to rename this page to "Layer 2 Tunneling Protocol", as this is the correct title. Any comments? Web-Crawling Stickler 18:52, 8 March 2007 (UTC)

Which OSI model layer??
I have a book that says L2TP resides in the data-link layer (layer 2) of the OSI. Than this page says its in the session (layer 5) layer. Also, on the wikipedia article on the OSI Model, it is listed in the transport layer (layer 4). I am pretty confused... —Preceding unsigned comment added by 70.4.225.206 (talk) 22:04, 19 July 2008 (UTC)
 * This is a somewhat old post and I don't see any mention of OSI in the current version of this article. Still I thought i'd address it.
 * The problem is that OSI was based on a fixed idea of how a network should look. Real networks don't fit that model but authors often see the need to force them to fit anyway. Tunneling protocols are especially difficult because from the perspective of the user of the tunnel they are a link layer protocol but from the perspective of the network carrying the tunnel they are an application or transport layer protocol (TCP/IP doesn't really have presentation or session layers). Plugwash (talk) 16:01, 6 August 2013 (UTC)

Road Warrior-style?
The page reads:

The help info does say that IPsec without L2TP is not to be used for Road Warrior-style VPNs. They advise to use L2TP/IPsec or PPTP for that.

What on earth is a Road Warrior-style VPN? —Preceding unsigned comment added by 66.74.218.162 (talk) 22:11, 3 May 2009 (UTC)

Removed contents copied from IBM Infocenter
This edit added contents taken from IBM's Infocenter and is therefore removed:


 * http://publib.boulder.ibm.com/infocenter/iseries/v5r3/topic/rzaiy/rzaiyl2tpsupport.htm
 * http://publib.boulder.ibm.com/infocenter/iseries/v5r3/topic/rzaiy/rzaiyvoltunnel.htm
 * http://publib.boulder.ibm.com/infocenter/iseries/v5r3/topic/rzaiy/rzaiycomptic.htm
 * http://publib.boulder.ibm.com/infocenter/iseries/v5r3/topic/rzaiy/rzaiycomptrd.htm
 * http://publib.boulder.ibm.com/infocenter/iseries/v5r3/topic/rzaiy/rzaiymultihop.htm

Fontoponto (talk) 06:58, 18 September 2010 (UTC)

USRobotics?
This article says that PPTP is from US Robotics, while PPTP says it's from Microsoft, 3Com, and others.

Which is correct? --MathsPoetry (talk) 07:59, 21 September 2013 (UTC)

External links modified
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Layer 2 tunnelling protocol provides a layer 2 tunnel through which layer 1 is passed.
So the statement in the lead paragraph that "it provides a tunnel for Layer 2" is confusing because it is wrong. Layer 3 is a tunnel for layer 2: layer 2 is a tunnel for layer 1: layer 1 is a point to point protocol. Let's think of some other ways of saying it correctly: "The protocol provides a layer 2 tunnel", "The protocol provides a tunnel through which layer 1 is passed"

Internet Protocol is not a provider for IP packets. TCP is not a provider for Transmission Control Packets. The Layer 2 protocol isn't a "provider" for layer 2: it's a 'protocol' for layer 2: it's a "provider" for layer 1 and/or layer 3.

 ‘When I use a word,’ Humpty Dumpty said in rather a scornful tone, ‘it means just what I choose it to mean–neither more nor less.’, and that's Wikipedia editing. But for Wikipedia readers it's helpful if we stick to the common meaning of words and terms. 1.159.36.184 (talk) 10:39, 29 May 2023 (UTC)