TcpClient and SocketException

[Guest]

Hi,

I am developing a C# application to send requests to mail server to check
email addresses validity. I use a TcpClient object to connect to it with the
Connect(String hostname, Int32 port) method.
When I use my application at home I don't have any problem to connect and
get responses but when I try at work, I get the SocketException number 10061
: "target machine actively refused it". I don't have any proxy, maybe a
firewall.

My question is to know if there is another way to connect the servers (same
problem with sockets) or if there are existing parameters of the TcpClient
object to connect thru a firewall...

Thanks

 

[Bela Istok]

Hello Julien, As far I know, there is no way to do this, you need to open
the port in the firewall to do the connection.

Regards,

Bela Istok

 

[Hadi Hariri]

Julien

Sounds like you are not permitted to make a connection on the SMTP port
(normally 25) due to firewall restrictions.

 

[Guest]

It's what I was thinking :\

Just another point, when I use email verifier softwares from this network,
it is working. So it could possible to do it !?

 

[Hadi Hariri]

It's what I was thinking :\

Just another point, when I use email verifier softwares from this
network, it is working. So it could possible to do it !?

How does th email verifier work?

 

[Guest]

I don't know but it should connect on the remote smtp server !?

 

[Hadi Hariri]

Well what do you define by verified by email? Normally to allow
relaying (not really connection), they either use authentication or POP
before SMTP. You need to know what it's doing to be able to simulate it.