I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART, please see the FAQ at <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq> Document: draft-ietf-intarea-nat-reveal-analysis-05 Reviewer: Peter Yee Review Date: Mar-08-2013 IETF LC End Date: Mar-08-2013 IESG Telechat date: TBD Summary: This draft is on the right track but has open issues, described in the review. [Ready with issues.] This draft catalogs and analyzes various means of supplying a host identifier to a remote server when Carrier Grade NAT or similar host obscuring technology is in use. General: There were sentences in the draft that I could not parse even in the context of surrounding text. That's primarily why I'm marking this draft as "Ready with issues". These sentences are supplied below. Mostly, the document has a fair number of nits. The general concept is fine. General: hyphenate uses of "address sharing" when it used as an adjective. For example, "address-sharing device". General: expand acronyms on first use except if they are really well known in our community (e.g., TCP/IP) or where they appear in the abstract. Examples of acronyms in need of expansion are HIP, XFF, ?. General: You will probably want to resolve Internet Draft references to something more permanent. General: The term "broken" should be replaced with something more specific or useful. I've made some suggestions below. Section 1, 2nd paragraph, last sentence: delete "an" before "information". Section 1, 3rd paragraph: change "are" to "include". Section 1, 3rd paragraph: change "customers unsatisfaction" to "and customers' dissatisfaction". Section 2, 1st paragraph, 2nd sentence: delete "an" before "extra". Change "than" to "beyond". Section 2, 1st paragraph, 3rd sentence: replace this sentence with "We call this information the HOST_ID." Section 2, 2nd paragraph: add a serial comma after "subscriber". Serial comma use in the draft was inconsistent. Section 2, 3rd paragraph, 3rd sentence: I'm not sure why the HOST_ID and public IP address would be "relatively" unique. Assuming that HOST_IDs are unique amongst the hosts hidden behind the public IP address and the public IP address is unique, I would have thought that the combination was globally unique. My confusion may arise from the 4th sentence which is incomplete. Perhaps those two sentences could be rewritten for clarity. Section 2, 4th paragraph, 1st sentence: change "put" to "conveyed". Section 2, 4th paragraph, 2nd sentence: change "put" to "conveyed". Section 3, 2nd paragraph, 1st sentence: considering using "identifiability" instead of "uniqueness". Section 3, 2nd paragraph, 2nd sentence: replace "which" with "what". Section 3,1, 4th paragraph: add a comma after "re-write". Change "re-write" to "rewrite". Section 3.1, 5th paragraph: I don't quite follow what's being said here. Is the point that the address-sharing function should reveal the same HOST_ID for any given host regardless of what layer or mechanism that HOST_ID is being conveyed across? How does this relate to interference between HOST_IDs? Section 4.1.1, 1st paragraph, 1st sentence: delete "an" before "information". Section 4.1.1, 1st paragraph, 3rd sentence: insert ", there are" after "hence". Section 4.1.1, 4th paragraph, consider replacing with: "Address-sharing devices using this solution would be required to indicate that out of band, possibly using a special DNS record." Section 4.1.2, 3rd paragraph, 2nd sentence: add a comma after "scenario". Change "broken" to "ill-advised". Section 4.2.1, 1st paragraph, 2nd sentence: add "A " at the beginning of the sentence. Section 4.2.1, 1st paragraph, 4th sentence: rewrite as "This IP option allows the conveyance of an IPv4 address, an IPv6 prefix, a GRE key, an IPv6 Flow Label, etc." Section 4.2.1, 2nd paragraph: insert "an" before "IP". Section 4.2.2, 1st paragraph, 1st sentence: change "for" to "to". Section 4.2.2, 1st paragraph, 2nd sentence: use of the term "filter" in this sentence is not clear. Do you mean that that routes and middleboxes remove the IP options? Or that they remove packets with IP options? Or that they take other actions based on the presence of IP options? Please clarify. Section 4.2.2, 2nd paragraph: replace "As a" with "In". Define "host-hint" somewhere. Is it meant to be equivalent to HOST_ID? Section 4.3.1, 3rd sentence: change "their" to "its" both places in the sentence. Insert "or" before "subscriber". Section 4.3.2, 2nd paragraph, 2nd sentence: insert "a" before "HOST_ID" Section 4.3.2, 2nd paragraph, 3rd sentence: change "in host" to "on the host". Insert "the" before "address", and add a comma after "function". Section 4.3.2, 1st bullet item: this is the IETF. We don't need no stinkin' OSI! :-) Section 4.3.2, 1st bullet item, 2nd sentence: replace the sentence with "Moreover, an updated version of [I-D.wing-nat-reveal-option] no longer allows conveyance of a full IP address as the HOST_ID is encoded in 16 bits." Section 4.3.2, 2nd bullet item, 1st sentence: delete the comma after "limited". Section 4.3.2, 2nd bullet item, 4th sentence: delete the comma after "ACK". Section 4.3.2, 2nd bullet item, 5th sentence: move "only" before "allows". Change "to enclose" to "enclosing". Section 4.3.2, 3rd bullet item, 3rd sentence: the characterization of HOST_ID as leaked information seems pejorative. And how is a "communication leg" defined? Is this a standard term for communications between a CGN and a remote server, or for other backbone-carried communications? Section 4.3.2, 4th bullet item, append a comma after "particular". Section 4.3.2, 5th bullet item, 1st sentence: replace "to" with "the". Change "preserve" to "preservation of". Section 4.3.2, 5th bullet item, 3rd sentence: change "to reveal" to "revealing". Section 4.4.1, 1st paragraph, 1st sentence: move "not" before "to". Change "at" to "within". Change "which" to "that". Section 4.4.1, 1st paragraph, 2nd sentence: change "This" to "The". Append "of the conveyed information" after "format". Section 4.4.1, 2nd paragraph, 3rd sentence: change "their" to "its". Section 4.4.1, 3rd paragraph: insert "the" before "X-Forwarded-For". Section 4.4.2, 1st paragraph, 1st sentence: delete "the" before "address". Section 4.4.2, 2nd paragraph, 1st sentence: specify by whom the initiative was launched. Section 4.4.2, 2nd paragraph, 2nd sentence: append "who are" after "Wikipedia". Section 4.4.2, 4th paragraph, 1st sentence: would "transited" be more appropriate than "crossed"? Insert "the" before "Forwarded". Section 4.4.2, 6th paragraph: change "implementation" to "implementations". And that begs the question: implementations of what? Delete "some" before "parsing". Insert "an" before "XFF". Section 4.4.2, 7th paragraph: why is this "may be broken"? Either the Forwarded header can be injected or it cannot. Under encryption, the only way I can see to insert the header is if the encrypted TLS session is passing through a man-in-the-middle proxy that is spoofing both of ends of the communication in order to be able to transparently decrypt the traffic. Section 4.5.1, 1st paragraph, 4th sentence: insert "The" before '"PROXY"'. Section 4.5.2, 1st paragraph, last sentence: change "raise" to "arise". Append a comma after "firewalls". Section 4.5.2, 2nd paragraph: change "broken" to "infeasible". Change "can not" to "cannot". Section 4.6.1, 3rd paragraph: replace "do" with "are". Change "require" to "required". Section 4.6.1, 4th paragraph: insert "an" before "option". Section 4.6.2, 3rd paragraph: move "also" before "offering". I presume the "IP connectivity services" are those being offered to the host being identified, but that should be made clear in the text since the sentence is vague as to which end of the conversation is being reference. Section 4.7.1: delete "an" before "identity". Section 4.7.2, 2nd paragraph, 1st sentence: insert "having" after "is". Section 4.7.2, 2nd paragraph, 2nd sentence: delete "ported to be". Section 4.8, title: insert "of" after "Use". Section 4.8.1, 2nd paragraph, 2nd sentence: replace "differentiating" with "host-identifying". Section 4.8.2, 1st bullet item: insert "The" before "Address" and then make "Address" lower case. I'm not sure what this sentence is trying to tell me, however. Section 4.8.2, 2nd bullet item: replace "an" with "that the". Section 4.8.2, 4th bullet item: delete "Some" before "implementation" and then capitalize "implementations". Delete "to" before "delay" and append "of" after "delay". Change "receiving" to "receipt of". Delete the comma after "Request". Section 4.8.2, 5th bullet item: delete "may" before "receive" and then change "receive" to "receives". Section 4.8.2, 8th bullet item: delete "a". Section 4.8.2, 9th bullet item, 2nd sentence: change the first "are" to "is". Delete "to be". Section 4.9.1, 2nd paragraph, 2nd sentence: insert "the" before "address". Append a comma after "IDENT". Section 4.9.1, 2nd paragraph, 4th sentence: change "16 bit" to "16-bit". Section 4.9.2, 1st bullet item, 2nd sentence: change "Alternatives" to "Alternative". Change "mechanism" to "mechanisms". Change "design" to "designed". I don't think you want the list of other transport mechanisms to include TCP since you've already said that IDENT is specific to TCP. Section 4.9.2, 3rd bullet item, 1st sentence: insert "that" before "the address". Insert "the" before "IDENT". Section 4.9.2, 4th bullet item, 2nd sentence: change "This" to "Such a". Change "deployable" to "feasible". Delete "heavy and" unless you want to explain what heavy means. Section 4.9.2, 5th bullet item: delete "Some" and capitalize "implementations". Delete "to" before "delay" and append "of" after "delay". Change "receiving" to "receipt of". Delete the comma after "response". Section 4.9.2, 6th bullet item: delete "a". Section 4.9.2, 7th bullet item, 1st sentence: change "are" to "is". Section 4.9.2, 7th bullet item, 2nd sentence: change "even" to "further". Section 4.9.2, 9th bullet item: change "non legitimate" to "illegitimate". Section 5, 1st paragraph after the Table 1 caption: append a comma after "[Options]". Insert ", and" before "ExtendTCP". Section 5, 2nd paragraph after the Table 1 caption: change "Address" to "address". Section 5, 3rd paragraph after the Table 1 caption: change "to establish" to "for establishing". Section 5, 4th paragraph after the Table 1 caption, 3rd sentence: change "hold" to "delay". Change "receiving" to "receipt of". Section 5, 4th paragraph after the Table 1 caption, 4th sentence: change "at" to "on". Section 5, 5th paragraph after the Table 1 caption, 3rd sentence: change "hold" to "delay". Change "receiving" to "receipt of". Insert "the" before "IDENT". Section 5, 5th paragraph after the Table 1 caption, 4th sentence: change "at" to "on". Consider rewriting this sentence and the similar one in the previous paragraph for even greater clarity. Section 7, 3rd paragraph: insert "used" before "to convey". Section 8, 1st paragraph: append a comma after "Halpern". Section 8, 2nd paragraph: append a comma after "Wing". Section 8, 4th paragraph: change to "The privacy text was provided by A. Cooper."