Comment 1 for bug 1696202

I just tried subscribing to <email address hidden> from the page at <https://mail.python.org/mailman/listinfo/mailman-users>. This list has private rosters and the subscription process went completely normally. Upon submitting the form, I was sent to the subscribe results page and all was as expected.

There is in issue with load balancers and perhaps proxies. The IPv4 address that submits the form has to match the address that did the GET of the form. It used to have to match exactly, but because of load balancer issues we've seen it now only has to match the first 3 octets <https://bugs.launchpad.net/bugs/1447445>.

Maybe there is some IP change issue and changing private_roster was just a coincidence.

I've looked at logs and I see

Jun 05 11:15:42 2017 (21148) pycon-pune: pending Anwesha ...
Jun 05 11:25:35 2017 (23837) pycon-pune: pending Kushal ...
Jun 05 20:42:26 2017 (18559) pycon-pune: pending Kushal ...
Jun 06 07:32:48 2017 (9267) pycon-pune: pending Sayan ...
Jun 06 14:13:45 2017 (5012) pycon-pune: pending Terri Test ...

Associated with some of those, I see successful GETs of the listinfo and POSTs of the form. I also see these GETs and posts shortly before the successful Terri Test subscribe.

/var/log/apache2/mail.python.org-ssl_access.log:134.134.139.75 - - [06/Jun/2017:14:06:21 -0400] "GET /mailman/listinfo/pycon-pune HTTP/2.0" 200 2292 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"
/var/log/apache2/mail.python.org-ssl_access.log:192.55.55.41 - - [06/Jun/2017:14:08:31 -0400] "GET /mailman/listinfo/pycon-pune HTTP/2.0" 200 2291 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"
/var/log/apache2/mail.python.org-ssl_access.log:134.134.139.75 - - [06/Jun/2017:14:08:42 -0400] "POST /mailman/subscribe/pycon-pune HTTP/2.0" 200 546 "https://mail.python.org/mailman/listinfo/pycon-pune" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"
/var/log/apache2/mail.python.org-ssl_access.log:134.134.139.75 - - [06/Jun/2017:14:09:15 -0400] "GET /mailman/listinfo/pycon-pune HTTP/2.0" 200 2293 "-" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"
/var/log/apache2/mail.python.org-ssl_access.log:192.55.55.41 - - [06/Jun/2017:14:09:24 -0400] "POST /mailman/subscribe/pycon-pune HTTP/2.0" 200 546 "https://mail.python.org/mailman/listinfo/pycon-pune" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"
/var/log/apache2/mail.python.org-ssl_access.log:192.55.55.41 - - [06/Jun/2017:14:12:02 -0400] "GET /mailman/listinfo/pycon-pune HTTP/2.0" 200 2292 "https://mail.python.org/mailman/admin/pycon-pune/digest" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"
/var/log/apache2/mail.python.org-ssl_access.log:134.134.139.75 - - [06/Jun/2017:14:12:51 -0400] "POST /mailman/subscribe/pycon-pune HTTP/2.0" 200 546 "https://mail.python.org/mailman/listinfo/pycon-pune" "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/58.0.3029.110 Chrome/58.0.3029.110 Safari/537.36"

These look like two different IPs doing GET and POST and that should be OK, but may be an issue somehow.

I also installed the not well tested fix for <https://bugs.launchpad.net/mailman/+bug/1695667> at about 13:20 on 06 June, so that could be involved, but as I said, it worked for me on Mailman-users with private_roster set to admin only.