Hi all, My exchange 2010 SP1 started to experience connectivity issues: EVENT ID 2105, Source MSExchange ADAccess Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=1128). Exchange Active Directory Provider failed to obtain DNS records for domain jericho.local. DNS Priority and Weight for the Domain Controllers in this domain will be set to the default values 0 (priority) and 100 (weight). Process MAD.EXE (PID=5472). Exchange Active Directory Provider failed to obtain DNS records for domain jericho.local. DNS Priority and Weight for the Domain Controllers in this domain will be set to the default values 0 (priority) and 100 (weight). EVENT ID 54, Source MSExchange OWA The Active Directory system configuration session couldn't be retrieved. Exception message: "Active Directory server is not available. Error message: Active directory response: The LDAP server returned an unknown error.". EVENT ID 2070, Source MSExchange ADAccess Process MsFTEFD.exe (PID=7576). Exchange Active Directory Provider lost contact with domain controller . Error was 0x51 (ServerDown) (Active directory response: The LDAP server is unavailable.). Exchange Active Directory Provider will attempt to reconnect with this domain controller when it is reachable. First I thought it because AVG is installed on DC and on Exchange servers. But it continue even after AVG disabling. No problem with DC within Windows Logs. Also clients were unable to connect Outlook to Exchange. Outlook prompted for Login\pass. ipconfig /flushdns on each PC solved it. Please advice what can be wrong with exchange and network connection. P.S. dcdiag from exch.: C:\Users\administrator.mydomain>dcdiag /s:dc01.mydomain.local Directory Server Diagnosis Performing initial setup: * Identified AD Forest. Done gathering initial info. Doing initial required tests Testing server: Default-First-Site-Name\DC01 Starting test: Connectivity The host dac364a6-3a4a-4aa4-b097-6073d2c29bf4._msdcs.mydomain.local could not be resolved to an IP address. Check the DNS server, DHCP, server name, etc. Neither the the server name (dc01.mydomain.local) nor the Guid DNS name (dac364a6-3a4a-4aa4-b097-6073d2c29bf4._msdcs.mydomain.local) could be resolved by DNS. Check that the server is up and is registered correctly with the DNS server. Got error while checking LDAP and RPC connectivity. Please check your firewall settings. ......................... DC01 failed test Connectivity Doing primary tests Testing server: Default-First-Site-Name\DC01 Skipping all tests, because server DC01 is not responding to directory service requests. Running partition tests on : ForestDnsZones Starting test: CheckSDRefDom ......................... ForestDnsZones passed test CheckSDRefDom Starting test: CrossRefValidation ......................... ForestDnsZones passed test CrossRefValidation Running partition tests on : DomainDnsZones Starting test: CheckSDRefDom ......................... DomainDnsZones passed test CheckSDRefDom Starting test: CrossRefValidation ......................... DomainDnsZones passed test CrossRefValidation Running partition tests on : Schema Starting test: CheckSDRefDom ......................... Schema passed test CheckSDRefDom Starting test: CrossRefValidation ......................... Schema passed test CrossRefValidation Running partition tests on : Configuration Starting test: CheckSDRefDom ......................... Configuration passed test CheckSDRefDom Starting test: CrossRefValidation ......................... Configuration passed test CrossRefValidation Running partition tests on : mydomain Starting test: CheckSDRefDom ......................... mydomain passed test CheckSDRefDom Starting test: CrossRefValidation ......................... mydomain passed test CrossRefValidation Running enterprise tests on : mydomain.local Starting test: LocatorCheck ......................... mydomain.local passed test LocatorCheck Starting test: Intersite ......................... mydomain.local passed test Intersite BUT THERE IS NO CONNECTIVITY PROBLEM FROM DC01. Thanks, Nick

On Thu, 13 Sep 2012 03:52:10 +0000, IT Jericho wrote: >My exchange 2010 SP1 started to experience connectivity issues: > >EVENT ID 2105, Source MSExchange ADAccess > >Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=1128). Exchange Active Directory Provider failed to obtain DNS records for domain jericho.local. DNS Priority and Weight for the Domain Controllers in this domain will be set to the default values 0 (priority) and 100 (weight). > >Process MAD.EXE (PID=5472). Exchange Active Directory Provider failed to obtain DNS records for domain jericho.local. DNS Priority and Weight for the Domain Controllers in this domain will be set to the default values 0 (priority) and 100 (weight). > >EVENT ID 54, Source MSExchange OWA > >The Active Directory system configuration session couldn't be retrieved. Exception message: "Active Directory server is not available. Error message: Active directory response: The LDAP server returned an unknown error.". > >EVENT ID 2070, Source MSExchange ADAccess > >Process MsFTEFD.exe (PID=7576). Exchange Active Directory Provider lost contact with domain controller . Error was 0x51 (ServerDown) (Active directory response: The LDAP server is unavailable.). Exchange Active Directory Provider will attempt to reconnect with this domain controller when it is reachable. > > > >First I thought it because AVG is installed on DC and on Exchange servers. But it continue even after AVG disabling. No problem with DC within Windows Logs. > >Also clients were unable to connect Outlook to Exchange. Outlook prompted for Login\pass. ipconfig /flushdns on each PC solved it. > >Please advice what can be wrong with exchange and network connection. The event log and the DCDIAG both say there's a problem with DNS and LDAP. The DNS thing may not be a "connectivity" problem but if the names aren't in the DNS zone your server isn't going to be able to use the DC or GC. That inability to locate the ldap services (which are SRV records in DNS) may be the cause of the LDAP failure. So, figure out why DNS resolution fails and fix the problem. It isn't an Exchange problem, though -- it's a Windows/AD/DNS problem. Testing server: Default-First-Site-Name\DC01 Starting test: Connectivity The host dac364a6-3a4a-4aa4-b097-6073d2c29bf4._msdcs.mydomain.local could not be resolved to an IP address. Check the DNS server, DHCP, server name, etc. Neither the the server name (dc01.mydomain.local) nor the Guid DNS name (dac364a6-3a4a-4aa4-b097-6073d2c29bf4._msdcs.mydomain.local) could be resolved by DNS. Check that the server is up and is registered correctly with the DNS server. Got error while checking LDAP and RPC connectivity. Please check your firewall settings. ......................... DC01 failed test Connectivity --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

On Thu, 13 Sep 2012 03:52:10 +0000, IT Jericho wrote: >My exchange 2010 SP1 started to experience connectivity issues: > >EVENT ID 2105, Source MSExchange ADAccess > >Process MSEXCHANGEADTOPOLOGYSERVICE.EXE (PID=1128). Exchange Active Directory Provider failed to obtain DNS records for domain jericho.local. DNS Priority and Weight for the Domain Controllers in this domain will be set to the default values 0 (priority) and 100 (weight). > >Process MAD.EXE (PID=5472). Exchange Active Directory Provider failed to obtain DNS records for domain jericho.local. DNS Priority and Weight for the Domain Controllers in this domain will be set to the default values 0 (priority) and 100 (weight). > >EVENT ID 54, Source MSExchange OWA > >The Active Directory system configuration session couldn't be retrieved. Exception message: "Active Directory server is not available. Error message: Active directory response: The LDAP server returned an unknown error.". > >EVENT ID 2070, Source MSExchange ADAccess > >Process MsFTEFD.exe (PID=7576). Exchange Active Directory Provider lost contact with domain controller . Error was 0x51 (ServerDown) (Active directory response: The LDAP server is unavailable.). Exchange Active Directory Provider will attempt to reconnect with this domain controller when it is reachable. > > > >First I thought it because AVG is installed on DC and on Exchange servers. But it continue even after AVG disabling. No problem with DC within Windows Logs. > >Also clients were unable to connect Outlook to Exchange. Outlook prompted for Login\pass. ipconfig /flushdns on each PC solved it. > >Please advice what can be wrong with exchange and network connection. The event log and the DCDIAG both say there's a problem with DNS and LDAP. The DNS thing may not be a "connectivity" problem but if the names aren't in the DNS zone your server isn't going to be able to use the DC or GC. That inability to locate the ldap services (which are SRV records in DNS) may be the cause of the LDAP failure. So, figure out why DNS resolution fails and fix the problem. It isn't an Exchange problem, though -- it's a Windows/AD/DNS problem. Testing server: Default-First-Site-Name\DC01 Starting test: Connectivity The host dac364a6-3a4a-4aa4-b097-6073d2c29bf4._msdcs.mydomain.local could not be resolved to an IP address. Check the DNS server, DHCP, server name, etc. Neither the the server name (dc01.mydomain.local) nor the Guid DNS name (dac364a6-3a4a-4aa4-b097-6073d2c29bf4._msdcs.mydomain.local) could be resolved by DNS. Check that the server is up and is registered correctly with the DNS server. Got error while checking LDAP and RPC connectivity. Please check your firewall settings. ......................... DC01 failed test Connectivity --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP