Our company uses a filtering proxy which is setup correctly in /etc/environment and apt.conf.d
Regular internet access via http and https work but if I try to import a pgp key from keyserver.ubuntu.com it fails.
Example:
$ apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9
gpg: requesting key A88D21E9 from hkp server keyserver.ubuntu.com
gpgkeys: key 36A1D7869245C8950F966E92D8576A8BA88D21E9 can't be retrieved
gpg: no valid OpenPGP data found
Support says, that they found that the keyserver is not accepting a HTTP/1.0 header (see below) although the HTTP/1.0 is a valid request.
So they say the problem is on the keyserver side and they are not willing to do anything on their side.
I cannot really judge if that is true and I can also not find any contact for the Ubuntu keyserver to get a statement from, so I am stuck.
Trace gotten from zscaler proxy support :
GET /pks/lookup?op=get&options=mr&search=0x36A1D7869245C8950F966E92D8576A8BA88D21E9 HTTP/1.0
Cache-Control: no-cache
Pragma: no-cache
Connection: Close
X-Forwarded-For: 62.180.121.22*
Although this request is valid from RFC point of view, the server is denying it with a 400 Bad Request
error
HTTP/1.0 400 Bad Request
Server: squid/3.1.19
Mime-Version: 1.0
Date: Mon, 09 Mar 2015 09:39:47 GMT
Content-Type: text/html
Content-Length: 3346
X-Squid-Error: ERR_INVALID_URL 0
Vary: Accept-Language
Content-Language: en
X-Cache: MISS from cassava.canonical.com
X-Cache-Lookup: NONE from cassava.canonical.com:11371
Via: 1.0 cassava.canonical.com (squid/3.1.19)
Connection: close*