I tried to configure MS DTC via our VPN. But when I try to open the connection it gives me the following error.
The MSDTC transaction manager was unable to push the transaction to the destination transaction manager due to communication problems. Possible causes are: a firewall is present and it doesn't have an exception for the MSDTC process, the two machines cannot find each other by their NetBIOS names, or the support for network transactions is not enabled for one of the two transaction managers. (Exception from HRESULT: 0x8004D02A)
When I check with the network team they told me that the firewall is already configured to allow DTC.
If I explain this further this communication is done via VPN. According to my network admin, although the client machine could see the NetBios name of the server but server cannot see the client's NetBios name, when this communication is done through a firewall/router. He is telling that, to start a DTC communication both machines should be able to see their NetBios names.
I tried with DTCPing (Same setup) and the dtc ping error is
03-04, 10:18:33.918-->RPC server:NGSVR received following information:
Network Name: NGSVR
Source Port: 49179
Partner LOG: WS-PCSPOS76036.log
Partner CID: EBA77A41-C9F9-4162-B7A2-E10404719072
++++++++++++Start Reverse Bind Test+++++++++++++
Received Bind call from WS-PCSPOS7
Network Name: NGSVR
Source Port: 49179
Hosting Machine:NGSVR
03-04, 10:18:33.996-->Trying to Reverse Bind to WS-PCSPOS7...
Test Guid:EBA77A41-C9F9-4162-B7A2-E10404719072
gethostbyname can not resolve WS-PCSPOS7
Error(0xB7) at nameping.cpp #43
-->gethostbyname failure
-->183(Cannot create a file when that file already exists.)
Can not resolve WS-PCSPOS7
Error(0x6BA) at ServerManager.cpp #453
-->RPC reverse BIND failed
-->1722(The RPC server is unavailable.)
Reverse Binding to WS-PCSPOS7 Failed
In GUID
Out GUID
Reverse BIND FAILED
Session Down
I have tried to open and do a transaction via non vpn setup and it was successful.
Can we configure MS DTC via VPN?
If it is possible any additional configuration should do to VPN?
Related
I wanted to make a ODBC connection from Windows PC to AS/400 DB2 server and I wrote a VBA program. But I got the following error.
Remote port could not be resolved
Then, I checked the status of server with CWSPING and got the result below:
I - Verifying connection to system 192.168.1.2...
I - Successfully connected to server application: Central Client
I - Successfully connected to server application: Network File
I - Successfully connected to server application: Network Print
I - Successfully connected to server application: Data Access
I - Successfully connected to server application: Data Queues
I - Successfully connected to server application: Remote Command
I - Successfully connected to server application: Security
E - CWBCO1011 - Remote port could not be resolved
E - CWBCO1008 - Unable to connect to server application DDM, returned 8407
I - Successfully connected to server application: Telnet
W - CWBCO1015 - Connection verified to system 192.168.1.2, but there were warnings
This means DDM service is not working on the server. ODBC connection requires DRDA, which runs upon DDM service, so I think running DDM service is the key to make ODBC connection. So I tried STRTCPSVR *DDM command but got the result below
*DDM not valid for parameter SERVER
And also tried CHGDDMTCPA AUTOSTART(*YES) PWDRQD(*YES) command, but got an error and I got stuck.
Command CHGDDMTCPA in library *LIBL not found
Does anyone have an idea of enabling DDM server on AS400?
Server: IBM AS400
OS version: V4R1
Try STRHOSTSVR *DATABASE.
STRHOSTSVR is used to start servers associated with IBM i Access and i Access Client Solutions.
STRTCPSVR is used, in general, to start servers associated with TCP/IP like FTP, Telnet, etc. Except the HTTP Server which is started via the Web Administration site at http://<server>:2001.
Additionally to the answer from #jmarkmurphy:
You can easily check netstat *cnn for open ports.
There is actually a tcpsvr named *ddm but that isn't used with ODBC.
ODBC-Access only needs host server *database. There aren't any further requirements for host servers.
For checking which services are started at tcp startup time, use strfdu, option 5 with the file qusrsys/qatocstart. From there you can easily view and change what should be started and what not.
Finally, I got connected by using JDBC. The summary of what I found is as follows:
ODBC seems using DRDA(port 446) but the server does not have DRDA/DDM service
OLEDB seems connecting Data Access(port 8471) but issued unknown error
JDBC also connection Data Access(port 8471) and it worked!
The first error I encountered when using ODBC is "Remote port could not be resolved". What happened behind this seems as follows:
ODBC asked Server Mapper(port 449) to find DRDA port(it may change on a server)
Server Mapper could not find DRDA port because the server has no DRDA service
ODBC showed "port not resolved" error
Then, I tried OLEDB this time. It checked user/password correctly but issued unknown error. When I put incorrect password, it showed "password is incorrect", which means OLEDB successfully log on to the server but got some error after sign on.
The last, I used JDBC and successfully connected! Generally, the connection url is like "jdbc:as400://" but it showed error. Using trace of JDBC, it seems to have problem on sign on to the server. So I changed the url to "jdbc:as400://:8471", then I finally connected. Looking into trace, it directly access to port 8741 and send user/password and get connected. I don't know the detail, but it worked!
Appreciated for your help!
Occasionally I get this error when working on remote computers. It's hit or miss on which computer I get it on. But I am able to ping the computer and test-connection pans out. For example, the computer I got this error on today I was able to get to yesterday. I know the computer is on because It's right next me.
Get-WmiObject : The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
At line:1 char:14
+ get-wmiObject <<<< -Class win32_operatingsystem -ComputerName $current -Authentication 6 -credential $credential | Invoke-WMIMethod -name Win32Shutdown
+ CategoryInfo : InvalidOperation: (:) [Get-WmiObject], COMException
+ FullyQualifiedErrorId : GetWMICOMException,Microsoft.PowerShell.Commands.GetWmiObjectCommand
Check to see if the Remote Procedure Call (RPC) service is running. If it is, then it's a firewall issue between your workstation and the server. You can test it by temporary disabling the firewall and retrying the command.
Edit after comment:
Ok, it's a firewall issue. You'll have to either limit the ports WMI/RPC work on, or open a lot of ports in the McAfee firewall.
Here are a few sites that explain this:
Microsoft KB for limiting ports
McAfee site talking about the same thing
You may get your answer here: Get-WmiObject : The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
UPDATE
It might be due to various issues.I cant say which one is there in your case. It may be because:
DCOM is not enabled in host pc or target pc or on both
your firewall or even your antivirus is preventing the access
any WMI related service is disabled
Some WMI related services are:
Remote Access Auto Connection Manager
Remote Access Connection Manager
Remote Procedure Call (RPC)
Remote Procedure Call (RPC) Locator
Remote Registry
For DCOM settings refer to registry key HKLM\Software\Microsoft\OLE, value EnableDCOM. The value should be set to 'Y'.
My problem turned out to be blank spaces in the txt file that I was using to feed the WMI Powershell script.
I had the same problem when trying to run a PowerShell script that only looked at a remote server to read the size of a hard disk.
I turned off the Firewall (Domain networks, Private networks, and Guest or public network) on the remote server and the script worked.
I then turned the Firewall for Domain networks back on, and it worked.
I then turned the Firewall for Private network back on, and it also worked.
I then turned the Firewall for Guest or public networks, and it also worked.
Duting create cluster, my error was:
An error occurred while creating the cluster.
Could not determine Management Point Network Type.
The RPC server is unavailable
Solution:
Server Manager
Local Server
Click on one of the network adapter links, like "Ethernet".
Control Panel\Network and Internet\Network Connections
Right click on the first network adapter
Internet Protocol Version 4 (TCP/IPv4)
Properties
Advanced
DNS
Click radio button:
Append primary and connection specific DNS suffixes
If anyone else is reading this eons later. My problem was I deployed a GPO a few months ago that disables printer spooling via Windows Firewall rules. One of the rules is "File and printer sharing (Spooler Service - RPC-EPMAP)". This was set to deny.
This blocked the "RPC Endpoint Mapper" port range inbound and didn't specify a service. As a result this was blocking all traffic inbound on all RPC ports (tcp 1024-5000).
Disables the rule and this magically started working again.
TLDR; You need to allow the RPC Endpoint Mapper port range inbound on Windows firewall (tcp 1024-500) along with the WMI-In rule.
So I have an application that connects to our SQLServer.
This works on any server behind the firewall just fine.
When i put it out on our live server, outside the firewall the connection to the sqlserver fails with this error
A network-related or instance-specific error occurred while establishing a connection
to SQL Server. The server was not found or was not accessible. Verify that the instance
name is correct and that SQL Server is configured to allow remote connections. (provider:
SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
I know this is due to the firewall though the network admin claims the firewall is allowing it through (has even gone to the point of saying "your doing it wrong")
What can I do to see where it is failing exactly to see if it really is the firewall and prove to him that it is.
I am using the IP of the machine so it is not a DNS issue.
Any other ideas?
With all due respect, your admin is right by telling you you're doing it wrong, assuming if what you mean by "outside the firewall" means outside of your company's network. Something like a database server should never be exposed to external connections.
Edit: Never mind, this is a connection from the DMZ.
So the only thing I can think of is to try and telnet to that machine on port 1433 (while logged into the web server) and see if you get a connection error. You're not using SSPI so I don't think security would be the issue.
If telnet fails then you can take that to your network admin as proof that the problem is the firewall.
Are you using a named instance? Make sure SQL Browsing Service is running.
Usually when you connect to the default instance on your local server you use '(local)'. When it's a named instance you would use '(local)\InstanceName'. Or (local) is replaced by a host name or ipaddress.
When you use a named instance you could run into connection problems when trying to connect from a remote server.
I was wondering if there is a way to see if a server blocks outgoing connections. I am trying to connect to an external database from a client's server.
This is the error I get:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.)
Edit:
I forgot to say I only have access to the plesk control panel. That's why I was asking if there is a way with asp.net.
When you say "server", do you mean the asp.net server, or the SQL server? And are both machines on the same network? Is this hosted?
Sql Server:
They can remove the OPENROWSET functionality, so you can't connect to remote servers, regardless
I doubt they are giving you access to linked servers in a hosted env
ASP.Net
You can try to connect to the other server via a regular connection, and see if that works.
Download a tracert component, and use that to try to trace from your server to the remote one.
If it dies somewhere inside your network, then that is your answer (it is blocked)
If it works, the outbound is open. Doesn't mean 1433 is open though.
If it dies after, not blocked, but maybe the remote is blocking icmp echo
Remember to try to tracert to somewhere else that you know works
It will be hard to tell what is killing the connection on 1433, if you can get to the server using other means. Could be the firewall, their fw, etc.
The trusty telnet method:
telnet theserver 1433
If this times out, the server is not listening. If the screen blanks and you can type something, the server is listening and no firewall is blocking the connection.
In Vista and Windows 7, you have to install telnet as a Windows component from Control Panel -> Programs and Features.
I have a login page that works in my local development environment. When I push the site onto the web server, i am getting this error when trying to login from the asp.net login control.
An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
I cannot figure out why it does not work on the server. Do I need to add anything or change something in the web.config?
This support article may help. It may also be a firewall issue or an authentication issue on the new setup (but the error message makes that less likely).
For resolving error 26 in sql server you need to do the following steps.
At Server System
1. Under surface area configuration manager-Open up remote connections.
2. Add into firewall 1433 and 1434 port no as n exception.
3. Open port 1433 on router for WAN access.
4. Add client machine ip address as an exception to your antivirus or allow LAN settings in antivirus.
5. Now try to check if both client and server are connected to each other.
for this type "ping IP address of remote system" at run and if reply is obtained then do same for server machine.
If reply is obtained from both machines.
Open Sql server and try to connect to remote machine which allow remote connections using its ip address. U will surely get connected to server machine
See this video
Check to make sure TCP/IP is enabled on the SQL Server. For whatever reason, named pipes and TCP/IP is off by default. Also make sure you are trying to connect to the correct instance (maybe you are using ./SQLEXPRESS locally and on the server SQL is installed on the default instance). Lastly, make sure the database you are trying to connect to exists on the server.