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Diffstat (limited to 'tor-spec.txt')
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diff --git a/tor-spec.txt b/tor-spec.txt index df0ca38..c073b1b 100644 --- a/tor-spec.txt +++ b/tor-spec.txt @@ -2146,6 +2146,54 @@ see tor-design.pdf. 0.2.4.19. Includes support for CREATE2 and CREATED2 and EXTEND2 and EXTENDED2. + Relay=2 has limited IPv6 support: + * Clients might not include IPv6 ORPorts in EXTEND2 cells. + * Relays (and bridges) might not initiate IPv6 connections in + response to EXTEND2 cells containing IPv6 ORPorts, even if they + are configured with an IPv6 ORPort. + + However, relays support accepting inbound connections to their IPv6 + ORPorts. And they might extend circuits via authenticated IPv6 + connections to other relays. + + "3" -- relays support extending over IPv6 connections in response to an + EXTEND2 cell containing an IPv6 ORPort. + + Bridges might not extend over IPv6, because they try to imitate + client behaviour. + + A successful IPv6 extend requires: + * Relay subprotocol version 3 (or later) on the extending relay, + * an IPv6 ORPort on the extending relay, + * an IPv6 ORPort for the accepting relay in the EXTEND2 cell, and + * an IPv6 ORPort on the accepting relay. + (Because different tor instances can have different views of the + network, these checks should be done when the path is selected. + Extending relays should only check local IPv6 information, before + attempting the extend.) + + When relays receive an EXTEND2 cell containing both an IPv4 and an + IPv6 ORPort, and there is no existing authenticated connection with + the target relay, the extending relay may choose between IPv4 and + IPv6 at random. The extending relay might not try the other address, + if the first connection fails. + + As is the case with other subprotocol versions, tor advertises, + recommends, or requires support for this protocol version, regardless + of its current configuration. + + In particular: + * relays without an IPv6 ORPort, and + * tor instances that are not relays, + have the following behaviour, regardless of their configuration: + * advertise support for "Relay=3" in their descriptor + (if they are a relay, bridge, or directory authority), and + * react to consensuses recommending or requiring support for + "Relay=3". + + This subprotocol version is described in proposal 311, and + implemented in Tor 0.4.4.1-alpha. + 9.4. "HSIntro" The "HSIntro" protocol handles introduction points. |