Red Hat Bugzilla – Bug 480096
ypbind can fail to bind if started soon after NetworkManager
Last modified: 2013-03-03 17:59:23 EST
Created attachment 329056 [details]
Patch for ypbind-mt. Apply after creating Fedora 10 version of source via "rpmbuild -bp ypbind.spec".
Description of problem:
When using DBus/NetworkManager, ypbind tries to resolve the IP address of
a named server even if no network is yet available to provide DNS. When server
lookup fails, ypbind silently falls into broadcast mode and never again tries
to resolve server addresses, even when a network becomes available. On
networks where broadcast from the client is not possible (e.g., if the server
is on a different network), binding never occurs.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Network connection should be handled via NetworkManager.
2. Set up a one-line /etc/yp.conf like:
domain mydomain server nis.mydomain.org
The server chosen should be on a network not accessible via broadcast
(i.e., on a different network), and the server must be specified
by name and not by IP address, since the bug is related to DNS
3. as root:
# service NetworkManager stop; service ypbind stop
# service NetworkManager start; /sbin/ypbind -d
Note that to see the failure, it is critical that ypbind be
started quickly after NetworkManager, so that DNS is not yet available
when ypbind starts. So keep the second line as one line.
The ypbind process will try forever to bind via broadcast and will never
The ypbind process should successfully bind to its specified server shortly
after it finds out via DBus that a network is available.
See the attached patch, which solves the problem. If dbus is being used,
ypbind will not try to resolve a server name until
NetworkManager indicates that a network is available. Also, with the
patches, ypbind will not "fall into" broadcast mode if dbus is being used.
Note that ypbind's broadcast mode poses some security risk (as noted in
the ypbind man page), and that entering broadcast mode silently with no
indication to do so from yp.conf or from ypbind's "-broadcast" flag is
probably a bad thing to do... This behavior is not in the raw version of
ypbind-mt, and is only added by patches in Fedora's distribution.
Note that in Step 3 of "Steps to Reproduce", the line for restarting can be
# service NetworkManager start; service ypbind start
and the bind will still fail. The advantage of starting ypbind by hand with the "-d" (debug) flag is that you will see the fallback to broadcast mode, and see the continuing failure to bind.
Reproduced. I think that it's reasonable change. Fixed and ready for testing in Rawhide.
I got the new RPM from Rawhide, and it fixes the problem. Thanks!
The patch breaks ypbind without NetworkManager. We have to find a way how to let know ypbind that NetworkManager is used - in the interval between start of ypbind and full functionality of NetworkManager.
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Changing to F-12 since this problem is still present.
Just as a note, I'm now running a stock copy of ypbind built from:
It does not show the bug described here. However, I know there are
patches that Fedora applied to the stock 1.20.4 distro of ypbind-mt,
and I don't know that 1.29.91 addresses issues dealt with by those
The patch has been improved in ypbind-1.20.4-22 (Fedora 12), and it should fix the issue.
The latest build is here:
*** Bug 507763 has been marked as a duplicate of this bug. ***
ypbind-1.20.4-23.fc12 has been submitted as an update for Fedora 12.
ypbind-1.20.4-23.fc12 has been pushed to the Fedora 12 testing repository. If problems still persist, please make note of it in this bug report.
If you want to test the update, you can install it with
su -c 'yum --enablerepo=updates-testing update ypbind'. You can provide feedback for this update here: http://admin.fedoraproject.org/updates/ypbind-1.20.4-23.fc12
ypbind-1.20.4-23.fc12 has been pushed to the Fedora 12 stable repository. If problems still persist, please make note of it in this bug report.