cyrus http proxy in murder HTTP/1.1 403 Forbidden

[Jean-Christophe Delaye]

Hello,

We're testing Cyrus3.0.9 in a murder configuration.
It works fine for imap/imaps services. I can access mailboxes from
differents frontend, and move mailboxes from on backend to another !

I'm now blocked with the calendar features in this configuration.
It works fine in both read and write mode directly from the backend.

http://backend.eurecom.fr/dav/calendars/user/xxxx/Default/

PUT
/dav/calendars/user/xxxx/Default/8d6377bb-7c3f-4a55-a183-a05dae6fce0d.ics
HTTP/1.1" (if-match="970dfe515581407e1f4eeaa887316530b3ef3020") =>
"HTTP/1.1 204 No Content"

I've configured http/https also on the frontend to enable accessing
calendars from there:

http://frontend.eurecom.fr/dav/calendars/user/xxxx/Default/

It work perfectly in read only mode from the frontend, but if I try to
do some changes, it does not complete with Forbidden message.

"PUT
/dav/calendars/user/xxxx/Default/8d6377bb-7c3f-4a55-a183-a05dae6fce0d.ics
HTTP/1.1" (if-match="970dfe515581407e1f4eeaa887316530b3ef3020") =>
"HTTP/1.1 403 Forbidden"

I've compiled backend and frontend with the same options

Server: Cyrus-HTTP/3.0.9 Cyrus-SASL/2.1.26 OpenSSL/1.0.0 Nghttp2/1.35.0
Zlib/1.2.11 LibXML2.9.5 SQLite/3.24.0 LibiCal/3.0 ICU4C/59.1 Jansson/2.10
WWW-Authenticate: Basic realm="frontend.eurecom.fr"
DAV: 1, 2, 3, access-control, extended-mkcol, resource-sharing
DAV: calendar-access, calendar-auto-schedule
DAV: calendar-query-extended, calendar-availability,
calendar-managed-attachments
DAV: calendarserver-sharing, inbox-availability
DAV: addressbook
Allow: OPTIONS, GET, HEAD, POST, PUT, PATCH, DELETE, TRACE
Allow: PROPFIND, REPORT, COPY, MOVE, PROPPATCH, MKCOL, LOCK, UNLOCK, ACL
Allow: MKCALENDAR
Content-Length: 0

The question is:
Is there specific configuration parameters to enable proxy http/https in
murder configuration ? I can't find usefull informations in the
documentation. I've seen the Interactive HTTP test program httptest, but
can't find parameters to simulate calendar clients.

Thank you