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Question
Friday, July 11, 2014 7:15 AM | 1 vote
Our company have two site (SiteA and SiteB), both have its own DC (SiteA.xx.local and SiteB.yy.local). A Windows 2012 Server setup a Terminal Service. All SiteB user will use remote desktop to connect to the Terminal Server.
Sometime it will prompted an error "A licensing error occurred while the client was attempting to connect (Licensing timed out). Please try connecting to the remote computer again." Before this error message shown, the connection box will show the status "Estimating connection quality" for a while (my last test this will stay for 2 min 30 sec. before Licensing timed out prompt).
When we face this error, the only way to solve it is to reboot the Terminal Server. Once reboot, everything will be fined, all user can connect again. But sometime later (no fixed time period, from two hours - two days), user will then have this problem. But we need to reboot server again.
I can't found in what situation this error will happened. But we do experienced the following situation.
1. Sometime the a RDS Connection just stopped directly. Then try to reconnect but failed. In this case, all other users are still using it.
2. I try to unplug a network connection for a client, it show the connection is lost and trying to reconnect. After I plug the network back. Cancel the reconnect process. Then open the remote desktop again it will have the error.
3. there has two machine will never have this problem (we have this problem for 3 months). no matter how the connection lost. it can built up the connection once the connection is back
I followed some forum to enable the netlogon.log. On the Server, I found:
1. [MISC] [872] In control handler (Opcode: 4): This log must there when the problem happened.
Not sure if the following log help:
1. NetpDcGetName: SiteA.xx.local. using cached information ( NlDcCacheEntry = 0x000000DE96694D50 )
2.DsGetDcName function returns 0 (client PID=2088): Dom:SiteA Acct:(null) Flags: NETBIOS RET_DNS
3. NetpDcInitializeContext: DSGETDC_VALID_FLAGS is c03ffff1
4. DsGetDcName function called: client PID=23532, Dom:(null) Acct:(null) Flags: LDAPONLY RET_DNS (I found some log will be Dom:SiteA install of Dom:(null) )
5. NlTimeoutApiClientSession: Unbind from server \SiteA-DC.Stingmars.hk.local (TCP) 0.
6. NlPrintRpcDebug: Couldn't get EEInfo for I_NetLogonSamLogonEx: 1761 (may be legitimate for 0xc000006e)
On the Client side: Not sure if the log can help:
07/11 11:56:01 [MISC] DsGetDcName function called: Dom:(null) Acct:(null) Flags: DS
07/11 11:56:01 [DNS] NlDnsHasDnsServers: DNS Server is NOT configured on this machine.
07/11 11:56:01 [MISC] NetpDcInitializeContext: DSGETDC_VALID_FLAGS is c01ffff1
07/11 11:56:01 [MISC] NetpDcGetName: SiteB using cached information
07/11 11:56:01 [MISC] DsGetDcName function returns 0: Dom:(null) Acct:(null) Flags: DS
07/11 11:56:01 [MISC] DsGetDcName function called: Dom:(null) Acct:(null) Flags: FORCE DS
07/11 11:56:01 [DNS] NlDnsHasDnsServers: DNS Server is NOT configured on this machine.
07/11 11:56:01 [MISC] NetpDcInitializeContext: DSGETDC_VALID_FLAGS is c01ffff1
07/11 11:56:01 [MAILSLOT] Sent 'Sam Logon' message to SiteB[1C] on all transports.
07/11 11:56:01 [CRITICAL] NlBrowserSendDatagram: No transports available
07/11 11:56:01 [CRITICAL] NetpDcGetNameNetbios: SiteB: Cannot NlBrowserSendDatagram. (1C) 53
07/11 11:56:01 [MISC] NetpDcGetName: NetpDcGetNameNetbios returned 1355
07/11 11:56:01 [CRITICAL] NetpDcGetName: SiteB: IP and Netbios are both done.
07/11 11:56:01 [MISC] DsGetDcName function returns 1355: Dom:(null) Acct:(null) Flags: FORCE DS
07/11 11:56:02 [MISC] DsGetDcName function called: Dom:(null) Acct:(null) Flags: LDAPONLY RET_DNS
07/11 11:56:02 [DNS] NlDnsHasDnsServers: DNS Server is NOT configured on this machine.
07/11 11:56:02 [MISC] NetpDcInitializeContext: DSGETDC_VALID_FLAGS is c01ffff1
07/11 11:56:02 [MISC] NetpDcGetName: SiteB using cached information
07/11 11:56:02 [MISC] DsGetDcName function returns 0: Dom:(null) Acct:(null) Flags: LDAPONLY RET_DNS
07/11 11:56:03 [SESSION] V6 Winsock Addrs: fe80::bd63:1d49:d8fd:724%12 (1) V6WinsockPnpAddresses List used to be empty.
07/11 11:56:04 [MISC] NlPingDcNameWithContext: Ping response timeout for SiteB-DC.Stingmars.cn.local.
07/11 11:56:04 [CRITICAL] NlPingDcNameWithContext: Can't ping the DC SiteB-DC.Stingmars.cn.local.
07/11 11:56:04 [MISC] NetpDcInitializeContext: DSGETDC_VALID_FLAGS is c01ffff1
Thanks
Kenneth Lai
All replies (7)
Tuesday, July 29, 2014 6:46 AM âś…Answered
Hi Kenneth,
In my experience this error is caused by a networking issue between the client and the server. I recommend you examine all network components (both hardware and software) between the client device and the server. Some examples of what to look at:
- Client NIC driver and firmware, configuration settings
- Server NIC driver and firmware. configuration settings
- Switch configuration and firmware
- Router configuration and firmware
Additionally you may need to capture and examine network traffic using Netmon/Wireshark/etc.
-TP
Monday, July 14, 2014 3:55 AM
Hi Kenneth,
Thank you for posting in Windows Server Forum.
Please check the setting and workaround as per below thread.
RDP connection hangs on "estimating connection quality"
http://social.technet.microsoft.com/Forums/en-US/18819bef-5c01-4849-9c61-afb7e8c8a581/rdp-connection-hangs-on-estimating-connection-quality?forum=winserverTS
In addition, also check below details.
Cause: If you are using Internet Protocol security (IPsec) to help protect traffic over TCP between clients and terminal servers, then packet fragmentation might occur. As a result, some packets might not reach their destination, and client connections to terminal servers might fail.
Solution: Configure IPsec to help protect traffic over UDP rather than over TCP.
Hope it helps!
Thanks.
Dharmesh Solanki
Tuesday, July 15, 2014 1:37 AM
Hi Dharmesh,
I try to publish the license server in AD Domain Service. (http://technet.microsoft.com/en-us/library/ee891215(v=ws.10).aspx). Let see if it solve/improve my issue.
In the past, when I find and change some setting on the Remote Desktop / AD, It will stable for 1 - 3 days. But then the same problem will happen again, connection will suddenly drop and can't connect (with Licensing Timeout error).
Thanks for your advice.
Kenneth Lai
Thursday, July 24, 2014 7:12 AM
The problem still existed.
However, I found if I change the client computer IP address. it can connect without server reboot. Another interesting point if I assign the failed IP address to other computer. That computer also can't connect to server.
Kenneth Lai
Friday, July 25, 2014 7:26 AM
Hi Kenneth,
Thanks for your comment.
Can you use the IP address for connecting between two computers?
From the description which you provided it seems that there is some issue related to particular IP address with Licensing. So suggest you to check whether there is any policy assigned for restriction for that Ip by IP Security policy.
Please check below article for more information.
Block an IP or IP Range Using Windows IP Security Policy
Hope it helps!
Thanks.
Dharmesh Solanki
Tuesday, July 29, 2014 6:18 AM
Hi Dharmesh,
Thanks for the suggestion.
I permit all access from any IP, any protocol in both TS Server and Domain Server. using "**IP Security Policies on Local Computer". ** But my problem still existed.
I am confusing if it is really blocked by IP. As all computer can access again one I reboot the TS Server, just by a random time, SOME computer is disconnected and can't connect more. The temporary solution I found is to change Client computer IP OR reboot the TS Server again.
Thanks
Kenneth Lai
Monday, June 5, 2017 1:34 AM
We had a similar problem that was caused by our firewall being set to only allow port 3389 over TCP. RDP was trying to use UDP for communication instead. Opening the UDP port in the firewall ACLs fixed the issue. It was very odd that we got a licensing error rather than something more helpful or meaningful.