DotNet + OpenPop library - succeed connect from localhost but fail from production server - openpop

I have an gmail account, configured to use pop for incoming.
I need to connect and read mail from dot net app using OpenPop
My OpenPop client try to connect to pop.gmail.com with port 995 SSL:
MyPop3Client.Connect("pop.gmail.com", 995, true);
I do succeed to connect if I run from my localhost server,
but when trying to connect from production server I get: "Server not found".
What could be the reason?

My problem was solved - it was a firewall program on production server which blocked required port.

Related

Connection timeout in AzureML studio

I'm trying to connect a VM I have in AzureML studio. I keep getting the following: Connection attempt timed out for ''. Verify that server is accessible and SSH service is accepting connections.
Go to your VM config and test your connection through the 'connect' tab. Is your test successful? If not, check if port 22 is blocked. Watch for automated blocking rules applied to your VM.
we have DSVM attach in preview - might be interesting for you: https://github.com/Azure/azureml-previews/tree/main/previews/dsvm-attach.

AS/400 DDM service not running

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!

ngrok not connecting to local server

So, I am running ngrok (current version) on my Mac OSx. But I am getting the following error:
Failed to complete tunnel connection
The connection to http://35504712.ngrok.io was successfully tunneled to your ngrok client, but the client failed to establish a connection to the local address localhost:3746.
Make sure that a web service is running on localhost:3746 and that it is a valid address.
The error encountered was: dial tcp xx.xx.xx.xx:3746: getsockopt: connection refused
I know my server is running properly, as I can actually click the link to my localserver in the error message and get a response from my server.
Any ideas on how to diagnose?
Have you made sure you're running ngrok inside your project directory, also can you still access localhost:3746?
Also what command are you using to start hosting the ngrok sever?

Qt connecttohost command showing connection refused from remote host

I am running an application in WEC 7 and trying to connect to remote system, and I am using QFtp for transferring some data. When I try to connect to remote host using connecttohost, I am able to find the host but the connection is not successful and shows me error connectionrefused from remote host.
I tried the following things :
I made an exception in firewall for ftp connections so that remote host can accept the connections.
I turned on the discovery for the folders.
I added an inbound rule for port 21
I checked the option for ftp in control panel/Programs/program and features/turn on windows features/internet information services ,
FTP server.

SocketException: No connection could be made because the target machine actively refused it XX.XXX.XX.XXX:443

I got 2 servers with two equal wcf services hosted on them and one client application server. I can connect to endpoints and send a requests to both services using test wcf client app (.NET Web Service Studio) from my local machine successfully. But when I am trying to connect from client application server using the same test wcf client app I successfully connected only to the one wcf service server, but I have got an error when connecting to another one:
System.Net.WebException: There was an error downloading 'https://XXX/XXX?wsdl'. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it XX.XXX.XX.XXX:443
I performed netstat -an | find "443" command in command prompt on the client server and on my local machine to find out the difference and here what I have got:
1. On my local machine:
2. On the client app server:
What I already tried to do on client application server is:
- turned off firewall;
- stopped windows firewall service
- uninstalled mcafee virusscan enterprise application.
(I tried to set "prevent mass mailing worms from send mail" first, but mcafee was in foreign language that I don't understand, so I just uninstalled it)
after running command netstat -aon | findstr "443" on client application server I have got this result:
but I still got an error.
Does anybody know how to solve this issue?
Could be the problem on the wcf service server side?
The solution was predictable simple one - firewall was blocking the port,
but it's important to notice that the issue was caused by firewall on the wcf service server side, but not on client application server, which is making the request to that service.
I asked the technical support of that server, and they made firewall changes.
After that error was disappeared.
I faced the same issue and tried different ways to fix this. Nothing works. Later i found the issue which is, the application i tried to run is https and in my IIS, https binding was not created. I created binding https with the website and it works.

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