I am trying to setup a SLES 11 SP4 VM in Virtualbox to use a specific http proxy for all traffic along with certs exported from Windows.

I have successfully added the proxy and certs to Firefox so that Firefox works without problems. I also have the http_proxy and https_proxy environment variables set to the proxy URL.

Now I am trying to get zypper to work. My specific test case is to try and add the repository needed to install git. I will include the output below. I also tried to retry without the SSL verification but the result was the same error as before.

Code:
$ sudo zypper addrepo https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo

Download (curl) error for 'https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo':
Error code: Connection failed
Error message: Failed to connect to 2620:113:80c0:8::13: Network is unreachable

Abort, retry, ignore? [a/r/i/? shows all options] (a): a
Abort, retry, ignore? [a/r/i/? shows all options] (a): ?

a - Skip retrieval of the file and abort current operation.
r - Try to retrieve the file again.
i - Skip retrieval of the file and try to continue with the operation without the file.
u - Change current base URI and try retrieving the file again.

[a/r/i/? shows all options] (a): a
Problem accessing the file at the specified URI:
Download (curl) error for 'https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo':
Error code: Connection failed
Error message: Failed to connect to 2620:113:80c0:8::13: Network is unreachable

Please check if the URI is valid and accessible.
$ sudo zypper addrepo https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo
Download (curl) error for 'https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo':
Error code: Connection failed
Error message: Failed to connect to 2620:113:80c0:8::13: Network is unreachable

Abort, retry, ignore? [a/r/i/? shows all options] (a): ?

a - Skip retrieval of the file and abort current operation.
r - Try to retrieve the file again.
i - Skip retrieval of the file and try to continue with the operation without the file.
u - Change current base URI and try retrieving the file again.
s - Disable SSL certificate authority check and continue.

[a/r/i/? shows all options] (a): s
SSL certificate authority check disabled.
Abort, retry, ignore? [a/r/i/? shows all options] (a): r
Download (curl) error for 'https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo?ssl_verify=no':
Error code: Connection failed
Error message: Failed to connect to 2620:113:80c0:8::13: Network is unreachable

Abort, retry, ignore? [a/r/i/? shows all options] (a): a
Abort, retry, ignore? [a/r/i/? shows all options] (a): a
Problem accessing the file at the specified URI:
Download (curl) error for 'https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo?ssl_verify=no':
Error code: Connection failed
Error message: Failed to connect to 2620:113:80c0:8::13: Network is unreachable

Please check if the URI is valid and accessible.
Interestingly I could use curl to download the content of the address, but only if I passed the --insecure flag.

Code:
$ curl --insecure https://download.opensuse.org/repositories/devel:tools:scm/SLE_11_SP4/devel:tools:scm.repo
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>301 Moved Permanently</title>
</head><body>
<h1>Moved Permanently</h1>
<p>The document has moved <a href="https://download.opensuse.org/repositories/devel:tools:/scm/SLE_11_SP4/devel:tools:scm.repo">here</a>.</p>
<hr>
<address>Apache/2.4.23 (Linux/SUSE) Server at download.opensuse.org Port 443</address>
</body></html>
Any ideas how I can approach solving this?