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Bug 2006762 - RFE: systemd-resolved: add a way to disable synthetic RR generation
Summary: RFE: systemd-resolved: add a way to disable synthetic RR generation
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 9
Classification: Red Hat
Component: systemd
Version: 9.0
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Jacek Migacz
QA Contact: Frantisek Sumsal
URL:
Whiteboard:
Depends On: 2006761 2138081
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-09-22 11:05 UTC by François Cami
Modified: 2023-05-09 10:33 UTC (History)
16 users (show)

Fixed In Version: systemd-252-3.el9
Doc Type: If docs needed, set a value
Doc Text:
Clone Of: 2006761
Environment:
Last Closed: 2023-05-09 08:21:58 UTC
Type: Bug
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Github redhat-plumbers systemd-rhel9 pull 64 0 None open (#2006762) resolved: synthesize option 2022-02-01 21:45:20 UTC
Github systemd systemd pull 22599 0 None open resolved: synthesize option 2022-02-22 15:02:48 UTC
Red Hat Issue Tracker RHELPLAN-100124 0 None None None 2021-10-18 12:17:24 UTC
Red Hat Product Errata RHBA-2023:2531 0 None None None 2023-05-09 08:22:25 UTC

Description François Cami 2021-09-22 11:05:44 UTC
+++ This bug was initially created as a clone of Bug #2006761 +++

Description of problem:

systemd-resolved always (reverse)-resolves the host's IP addresses and FQDN.
This can be harmful when an application (for instance, a DNS zone manager) is installed on the same server instance.
That application would expect NXDOMAIN to be returned if the current server's IP does not belong in an already managed reverse zone.

More details:
https://lists.freedesktop.org/archives/systemd-devel/2021-September/046856.html


How reproducible:

Always, see list post.



Expected results:

Being able to disable the generation of synthetic RRs.


Additional info:

The workarounds described in the mailing-list all imply changing the application in a more or less intrusive or fragile way. Being able to change resolved's behavior in its configuration file would be much more efficient.

Comment 8 Jacek Migacz 2022-03-11 19:11:01 UTC
Hi François,

with systemd 250, there is a $SYSTEMD_NSS_RESOLVE_SYNTHESIZE for resolvers using libnss.

Just a quick recap, for the systemd 250 host with address 192.168.254.2:

SYSTEMD_NSS_RESOLVE_SYNTHESIZE=1 getent -s hosts:resolve hosts 192.168.254.2; echo $?
192.168.254.2   host2006762 host2006762.local
0

[root@host2006762 ~]# SYSTEMD_NSS_RESOLVE_SYNTHESIZE=0 getent -s hosts:resolve hosts 192.168.254.2; echo $?
2

Looking at a sibling Bug 2006761, I propose to close this bug.

Comment 9 François Cami 2022-03-11 19:22:53 UTC
Hi Jacek,

I created the RHEL9 bug to make sure that systemd-resolved would not be shipped in RHEL9 without this fix.
I'll defer to Antonio (CC'd) to decide whether closing is acceptable for FreeIPA/Identity Management.

Thanks!
François

Comment 11 Jan Macku 2023-01-24 12:47:23 UTC
This issue should be fixed via rebase to systemd v252.

Comment 16 errata-xmlrpc 2023-05-09 08:21:58 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (systemd bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2023:2531


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