I have tried from this host, and many others, with and w/o firewalls and NAT. This systems does not seem to answer. It did work a couple of weeks ago.
root@ov:~# greenbone-certdata-sync --verbose
Greenbone community feed server - http://feed.community.greenbone.net/
This service is hosted by Greenbone Networks - http://www.greenbone.net/
All transactions are logged.
If you have any questions, please use the Greenbone community portal.
See https://community.greenbone.net for details.
By using this service you agree to our terms and conditions.
Only one sync per time, otherwise the source ip will be temporarily blocked.
receiving incremental file list
timestamp
13 100% 12.70kB/s 0:00:00 (xfr#1, to-chk=0/1)
sent 43 bytes received 114 bytes 62.80 bytes/sec
total size is 13 speedup is 0.08
rsync: failed to connect to feed.openvas.org (89.146.224.58): Connection refused (111)
rsync: failed to connect to feed.openvas.org (2a01:130:2000:127::d1): Network is unreachable (101)
rsync error: error in socket IO (code 10) at clientserver.c(125) [Receiver=3.1.2]
root@ov:~# greenbone-certdata-sync --version
9.0+alpha~git-a3a71d88-master
root@ov:~# greenbone-scapdata-sync --version
9.0+alpha~git-a3a71d88-master
root@ov:~# greenbone-nvt-sync --version
7.0+beta1
Greenbone Vulnerability Manager 9.0+alpha~git-a3a71d88-master
GIT revision a3a71d88-master
Manager DB revision 207
Copyright © 2010-2017 Greenbone Networks GmbH
License GPLv2+: GNU GPL version 2 or later
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
root@ov:~# gsad --version
Greenbone Security Assistant 9.0+alpha~git-0574cb16f-master
Copyright © 2010 - 2019 Greenbone Networks GmbH
License GPLv2+: GNU GPL version 2 or later
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
root@ov:~# openvassd --version
OpenVAS Scanner 7.0+beta1
GIT revision 145de68-master
Most new code since 2005: © 2019 Greenbone Networks GmbH
Nessus origin: © 2004 Renaud Deraison deraison@nessus.org
License GPLv2: GNU GPL version 2
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.