The Samba AD DNS Back Ends: Difference between revisions

From SambaWiki
(Added 'A note on DNS problems' section (was in the 'join as DC' howto before))
m (Corrected ls command)
Line 59: Line 59:
have the same inodes (what indicates, that they are hard-linked):
have the same inodes (what indicates, that they are hard-linked):


# la -i .../samba/private/sam.ldb.d/
# ls -lai .../samba/private/sam.ldb.d/
17344368 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344368 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344370 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344370 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344372 -rw-rw---- 2 root named 421888 11. Nov 17:53 metadata.tdb
17344372 -rw-rw---- 2 root named 421888 11. Nov 17:53 metadata.tdb
# la -i .../samba/private/dns/sam.ldb.d/
# ls -lai .../samba/private/dns/sam.ldb.d/
17344368 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344368 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344370 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344370 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb

Revision as of 21:26, 2 December 2012

Internal DNS

Developing and using the DNS server built into Samba. AD backend.

Status

As of early September 2012, the internal DNS server is fully functional, for both GSS-TSIG-signed and unsigned updates.

Configuration

There are three options that can be added to smb.conf to control the behavior of DNS at this point:

# Allow unsigned updates | don't allow any updates | only allow signed updates
allow dns updates = True | False | signed

# If recursive queries = yes is set, the following is also needed
dns forwarder = <ip addr of external dns server>

Known Issues

The samba_dnsupdate command sometimes doesn't work for signed updates. We're currenly investigating. Client systems like samba3 or Win7 work fine.

Tests

Run during make test

TDB_NO_FSYNC=1 make test TESTS=samba.tests.dns

Run against external servers (Windows or BIND)

SERVER_IP=<dns server ip> SERVER=<dns server name> REALM=<dns server domain name part> PYTHONPATH=`pwd`/bin/python ./source4/scripting/bin/subunitrun samba.tests.dns


BIND 9.8.0 DLZ plug-in

Dynamically loaded zones plug-in for BIND 9.8.0. AD backend.

Status

Module is built with Samba, handles RFC 1035 and RFC 2136


BIND & samba_dnsupdate

Non-AD backend, but works with older BINDs.

Status

samba_dnsupdate script shipped with Samba, lets BIND handle DNS and just dynamically modifies AD-related information.


A note on DNS problems

If you have problems with resolving the new added DNS entries, you maybe want to check the following:

Files in samba/private/dns/sam.ldb.d/ are hardlinks to samba/private/sam.ldb.d/. Maybe you've copied/moved it across filesystems and the hardlinking got lost and you're now running with two different copies of the databases at the moment.

If you "ls -i" on the two folders, you should see, that the following files have the same inodes (what indicates, that they are hard-linked):

# ls -lai .../samba/private/sam.ldb.d/
17344368 -rw-rw---- 2 root named  4251648 11. Nov 18:27 DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344370 -rw-rw---- 2 root named  4251648 11. Nov 18:27 DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344372 -rw-rw---- 2 root named   421888 11. Nov 17:53 metadata.tdb

# ls -lai .../samba/private/dns/sam.ldb.d/
17344368 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344370 -rw-rw---- 2 root named 4251648 11. Nov 18:27 DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb
17344372 -rw-rw---- 2 root named  421888 11. Nov 17:53 metadata.tdb

If the files in the two folders have different inode numbers, then they aren't hard-links. To fix this, stop samba, move the three files to a save place (just to have a backup/copy of it) and hard-link them again:

# cd .../samba/private/dns/sam.ldb.d/
# ln ../../sam.ldb.d/DC%3DDOMAINDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb .
# ln ../../sam.ldb.d/DC%3DFORESTDNSZONES,DC%3DSAMBA,DC%3DEXAMPLE,DC%3DCOM.ldb .
# ln ../../sam.ldb.d/metadata.tdb .

Now start samba again.