----- Original Message -----
> Hello all.
> I'm working on integrating AD trust feature in the forest of a large
> organization (Its network is not connected to the internet).
> First I tested the trust in "clean" environment (that i have deployed) to
> simulate production forest deployment , in the following configuration:
> The forest root domain : red.com
> Second Domain tree : blue.com
> IPA : linux.blue.com
> All the AD DCs are 2008 R2 server and 2008 R2 functional level.
> IPA server in installed on RHEL 7.
> With help of the mailing list, all works fine. Users from both red.com and
> blue.com are able to log into IPA domain.
> After the success, I proceeded to test the trust in organization's test
> The installation of the trust itself has completed successfully. But although
> users from red.com were able to log into IPA domain, users from blue.com
> After checking the sssd logs it seemed as blue.com domain is unknown to IPA.
> Therefore I ran " ipa trustdomain-find red.com " in both environments, to see
> if there are any differences.
> And indeed there were:
> While in the "clean" environment, the command returned both red.com and
> blue.com domains, in organization's test environment it returned only
> red.com .
> I tried to re fetch the domain with " ipa trust-fetch-domains red.com " but
> it returned the message - " No new trust domains were found".
> It made me think that maybe the AD is not returning all domains in the
> I opened wireshark on both environments and ran " ipa trust-fetch-domains
> red.com " to see what is been sent from AD to IPA.
> In both environments I seen the DsrEnumerateDomainTrusts request and
> Reading the content of response showed that in both environments, the
> response contained red.com and blue.com domain.
> After inspecting the structures that contain domains information
> (DS_DOMAIN_TRUSTS) , I noticed that in both environments the TrustAttribute
> of red.com is set to 0x0000000.
> But TrustAttribute of blue.com is set to 0x00000020 (
> TRUST_ATTRIBUTE_WITHIN_FOREST ) in the "clean" environment and to 0x00800000
> in the test environment.
> Reading MSDN for TrustAttribute , explains the following:
> If this bit is set, then the trusted domain is within the same forest.
> Only evaluated on Windows Server 2003, Windows Server 2008, Windows Server
> 2008 R2, Windows Server 2012, and Windows Server 2012 R2.
> While I couldn't find specific information about 0x00800000, but this:
> 0x00400000 - 0x00800000
> Previously used trust bits, and are obsolete.
> I did not find more information on 0x00800000 or a reason why the attributes
> would be different in the two deployments.
> I asked for advice from Microsoft IT guy in the organization. He said that
> difference in the TrustAttribute is caused by the fact, that the "clean"
> environment was created as Windows Server 2008, while the test (and
> production) forest was created as windows 2000 servers (about 12 years ago)
> and the forest was gradually upgraded to 2003 and 2008 along the years.
> Couldn't find more information on the attribute for windows server 2000/2003
> but the theory sounds quite logical.
> I decided to check if TrustAttribute influences IPA's domain fetch.
> fetch_domains function in
> contains the following lines of code:
> trust_attributes = dict(
> NETR_TRUST_ATTRIBUTE_NON_TRANSITIVE = 0x00000001,
> NETR_TRUST_ATTRIBUTE_UPLEVEL_ONLY = 0x00000002,
> NETR_TRUST_ATTRIBUTE_QUARANTINED_DOMAIN = 0x00000004,
> NETR_TRUST_ATTRIBUTE_FOREST_TRANSITIVE = 0x00000008,
> NETR_TRUST_ATTRIBUTE_CROSS_ORGANIZATION = 0x00000010,
> NETR_TRUST_ATTRIBUTE_WITHIN_FOREST = 0x00000020,
> NETR_TRUST_ATTRIBUTE_TREAT_AS_EXTERNAL = 0x00000040)
> result = 
> for t in domains.array:
> if ((t.trust_attributes &
> trust_attributes['NETR_TRUST_ATTRIBUTE_WITHIN_FOREST']) and
> (t.trust_flags & trust_flags['NETR_TRUST_FLAG_IN_FOREST'])):
> res = dict()
> res['cn'] = unicode(t.dns_name)
> res['ipantflatname'] = unicode(t.netbios_name)
> res['ipanttrusteddomainsid'] = unicode(t.sid)
> res['ipanttrustpartner'] = res['cn']
> The bit-wise operation is preformed to check if the trust attribute is set to
> TRUST_ATTRIBUTE_WITHIN_FOREST (0x00000020) and if so, the trust is added to
> result array.
> It seems the value of TrustAttribute set to 0x00800000 is the reason the
> domain wasn't fetched.
> To confirm it I changed the if statement to:
> if ((t.trust_attributes &
> trust_attributes['NETR_TRUST_ATTRIBUTE_WITHIN_FOREST'] ||
> (t.trust_attributes & 0x00800000)) and (t.trust_flags &
> Then deleted and recreated the trust and finally ran " ipa
> trust-fetch-domains red.com "-
> this time the blue.com domain did appear!
> I was able to login with users from both red.com and blue.com to IPA domain.
> Checking both upstream 3.3 and 4.1 shows that the if statement was changed to
> if ( not ( t . trust_flags & trust_flags [ 'NETR_TRUST_FLAG_PRIMARY' ]) and
> ( t . trust_flags & trust_flags [ 'NETR_TRUST_FLAG_IN_FOREST' ])):
> From first sight it looks like blue.com will fetched.
> Haven't yet tested if upstream works in the test environment.
> Any thoughts on the subject will be great.
> (I hope i'm not mentioning something that was solved long ago).
The fix you see in the git repo was released in 3.3.3-28.el7_0.3, as
Can you please confirm that this version fixes the issue for you?
/ Alexander Bokovoy
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