There are three general parts to IPv6 support:
- Inbound Requests: Accepting requests from clients using IPv6. For example, a user visits https://phabricator.mycompany.com/ over IPv6.
- Outbound Requests: Sending requests from Phabricator to external IPv6 hosts. For example, a user tries to import a calendar event or an image macro from https://ipv6-image-macros.com/cat.jpg, where that host is IPv6-only.
- Intracluster Requests: Running Phabricator in a cluster on hosts in IPv6-only mode.
State of the world:
| Request Type | Status | Notes |
|---|---|---|
| Inbound | Supported | Phabricator should be able to receive requests from IPv6 clients. |
| Outbound | Mostly Not Supported | Phabricator can not make outbound HTTP requests to IPv6 hosts yet (SSH probably works). |
| Intracluster | Unknown | No one expressed interest in running an IPv6-only cluster yet. |
At the time of writing (Dec 2016) we haven't seen requests for outbound or intracluster support, so we don't have active plans to pursue them in the near term. I expect to pursue them as IPv6 is more widely adopted.
For inbound support:
- PhutilIPAddress only supports IPv4.
- PhutilCIDRBlock only supports IPv4.
- Double-check for remaining callers to ip2long() + integer IP address storage, and/or short address fields in the database. I believe we removed all of these already in anticipation of IPv6 support.
- We store or write remote addresses in some cases: push log, user activity log, access log, SSH log. These should be updated to use the preferred display form for addresses, so 1::1 and 1:0::1 are not different addresses.
For outbound support:
- Broadly, IPv6 URIs may appear in this general form: http://[2001:db8:85a3:8d3:1319:8a2e:370:7348]/
- We use PHP's parse_url() in PhutilURI, which can not parse IPv6 addresses as raw hostnames in URIs. The failure mode is that these requests are rejected, so this is safe, but you can't, e.g., import a Macro from a host with a raw IPv6 address.
- We use gethostnamebyl() to resolve hostnames, but this can only resolve IPv4 addresses. The failure mode is that these requests are rejected, so this is safe, but you can't import a Macro from an IPv6 host with no IPv4 address.
For cluster support:
- Not yet clear what issues may exist.