Reviewer: Stewart Bryant Review result: Almost Ready I am the assigned Gen-ART reviewer for this draft. The General Area Review Team (Gen-ART) reviews all IETF documents being processed by the IESG for the IETF Chair. Please wait for direction from your document shepherd or AD before posting a new version of the draft. For more information, please see the FAQ at <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>. Document: draft-ietf-opsawg-tacacs-13 Reviewer: Stewart Bryant Review Date: 2019-05-13 IETF LC End Date: None IESG Telechat date: 2019-05-16 Summary: There are a number of issues called out below that need addressing before publication. Someone needs to micro-check the text to make sure that all terms are defined and referenced. I picked up a few, but there were a lot I did not have time to check. Major issues: SB> The IANA section should ask IANA to point to this RFC as a reference SB> for port 49 ============ The first MD5 hash is generated by concatenating the session_id, the secret key, the version number and the sequence number and then running MD5 over that stream. All of those input values are available in the packet header, except for the secret key which is a shared secret between the TACACS+ client and server. SB> MD5 make a good checksum, but I am surprised to see it used in this SB> application in a new protocol. ============= All TACACS+ packets begin with the following 12-byte header. The header describes the remainder of the packet: SB> If ever there was an error in a long term session, how SB> how would you find in in the following packet structure? SB> Presumably from an incorrect major version and sequence number? SB> Some details on the error cases and the unconditional "safety" SB> of the protocol would be useful. ========== TAC_PLUS_AUTHEN_TYPE_ASCII := 0x01 TAC_PLUS_AUTHEN_TYPE_PAP := 0x02 TAC_PLUS_AUTHEN_TYPE_CHAP := 0x03 TAC_PLUS_AUTHEN_TYPE_ARAP := 0x04 (deprecated) TAC_PLUS_AUTHEN_TYPE_MSCHAP := 0x05 TAC_PLUS_AUTHEN_TYPE_MSCHAPV2 := 0x06 SB> There are lots of lists similar to the above. SB> I have not checked them all, but a number of the types SB> in this and subsequent parts of the design don't seem SB> to be defined or have a definitive reference =========== The START packet MUST contain a username and the data field MUST contain the PAP ASCII password. A PAP authentication only consists of a username and password RFC 1334 [RFC1334] . The REPLY from the server MUST be either a PASS, FAIL or ERROR. SB> Should there note be a note that RFC1334 is obsolete? =========== Minor issues: The use of the term "packet" as a unit of data is confusing, since the protocol is carried over TCP which is a streaming protocol. They are really TACAS+ PDUs ========= (For example, Cisco uses "tty10" to denote the tenth tty line and "Async10" to denote the tenth async interface). SB> Is it correct to quote a particular vendor in an RFC of this type? ======== TAC_PLUS_PRIV_LVL_MAX := 0x0f TAC_PLUS_PRIV_LVL_ROOT := 0x0f TAC_PLUS_PRIV_LVL_USER := 0x01 TAC_PLUS_PRIV_LVL_MIN := 0x00 SB> Where are these defined? ======== Nits/editorial comments: The normative description of Legacy features such as ARAP and SB> ARAP not expanded anywhere in document. ===== SB> telnet and rlogin need references ===== is the user is connected via ISDN or a POTS, SB> Are ISDN and POTS well known IETF terms? ===== It is not legal for an attribute name to contain either of the separators. It is legal for attribute values to contain the separators. SB> Is "legal" the correct term here?
