Lync DNS Records

Internal

lyncdiscoverinternal.contoso.com  (A record for the Autodiscover service for internal connections directed to internal Web services)

_sipinternaltls._tcp.contoso.com (SRV record for internal TLS connections)

_sipinternal._tcp.contoso.com (SRV record for internal TCP connections)

sipinternal.contoso.com (A record for the Front End pool)

Extarnal

lyncdiscover.contoso.com (A record for the Autodiscover service for external Web services)

_sip._tls.contoso.com (SRV record for external TCP connections)

sip.contoso.com (A record for the Front End pool when the client is on the internal network; A record for the Access Edge Server when the client is external with no VPN access)

sipexternal.contoso.com (A record for the Access Edge Server when the client is external with no VPN access)

Exchange 2010 EMC cannot access AD configuration data after you demote a DC

   Go to the folder and delete the Exchange Management Console file.

   C:\users\<specific user>\AppData\Roaming\Microsoft\MMC\Exchange Management Console

   Close EMC and reopen it.

DFS Replication problem -FIX

1. Connect to PDC domain controller:

Open services.msc --- and stop DFS Replication service

2. Open ADSI Edit (adsiedit.msc)
 connect to PDC
 go to ---
CN=SYSVOL Subscription,CN=Domain System Volume,CN=DFSR-LocalSettings,CN=<PDC Server >,OU=Domain Controllers,DC=<your domain>

change attributes :
msDFSR-Enabled=FALSE
msDFSR-options=1

on all other domain controllers change 
4. msDFSR-Enabled to  False

on PDC run :

5.repadmin /syncall pdc_name /APed

6. start  DFS Replication service

7. Go to ADSIEdit and change back msDFSR-Enabled to True
8. run DFSRDIAG POLLAD (on PDC)
9.  on all other Domain controllers run 

repadmin /syncall pdc_name /APed

10.  on all other DC (not PDC) change in ADSIEDIT msDFSR-Enabled to True
11. run on all DC (not PDC) DFSRDIAG POLLAD

Source

DFS Replication problem -FIX

1. Connect to PDC domain controller:

Open services.msc --- and stop DFS Replication service

2. Open ADSI Edit (adsiedit.msc)
 connect to PDC
 go to ---
CN=SYSVOL Subscription,CN=Domain System Volume,CN=DFSR-LocalSettings,CN=<PDC Server >,OU=Domain Controllers,DC=<your domain>

change attributes :
msDFSR-Enabled=FALSE
msDFSR-options=1

on all other domain controllers change (not PDC)
4. msDFSR-Enabled to  False

on PDC run :

5.repadmin /syncall pdc_name /APed

6. start  DFS Replication service

7. Go to ADSIEdit and change back msDFSR-Enabled to True
8. run DFSRDIAG POLLAD (on PDC)
9.  on all other Domain controllers run 

repadmin /syncall pdc_name /APed

10.  on all other DC (not PDC) change in ADSIEDIT msDFSR-Enabled to True
11. run on all DC (not PDC) DFSRDIAG POLLAD

Source

Exchange 2010: Unable to open Exchange Management Console – Initialization Failed

1. Close all MMC/EMC Instances before proceeding.
2. Open Powershell or Powershell IDE as the user you run the EMC under and execute the following command:.
3. Remove-ItemProperty -Path HKCU:\Software\Microsoft\ExchangeServer\v14\AdminTools\ -Name NodeStructureSettings
4. Close Powershell