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Hi,
I have a simple test application that allows me to send an email message through an Office 365 account. When I run this application from say my home PC it works fine, but when I run it from any machine on my company's network, it doesn't work.
The application allows for two different methods of sending a message, a simple smtp server address and a webservice. When running the application I get a different error for each method:
- smtp server: Quote: No connection could be made because the target machine actively refused it
- webservice: Quote: Autodiscover service couldn't be located
Our system administrator tells me our firewall is not blocking the port, and has not been able to suggest anything else. We only recently switched from third party Exchange 2010 to Office 365 and our on-premise AD is synced to it. MS Outlook works fine. Our office scanner also cannot send scans to email anymore, which it could through Exchange 2010's smtp server.
I am at a loss, and any help with this issue will be much appreciated.
Regards,
Johan
My advice is free, and you may get what you paid for.
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Quote: No connection could be made because the target machine actively refused it
Try to get the original error message send by the "target" (an SMTP error message or an ICMP message from a router/firewall at the target). It should be helpful.
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Hi,
Thanks for your reply. I set the application to specifically show smtp errors, but the error remains the same:
Quote: System.Net.Mail.SmtpException: Failure sending mail. -> 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 40.101.88.18:587
Quote: (an SMTP error message or an ICMP message from a router/firewall at the target)
The application works fine when I run it on any machine that is not on our network. Wouldn't that suggest that the error is caused by our own network, but somehow is not interpreted as a remote error?
I can ping 40.101.88.18 normally.
Regards,
Johan
My advice is free, and you may get what you paid for.
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Quote: No connection could be made because the target machine actively refused it
That means that there is no service listening on the specified port or a firewall is blocking the request (at the target side). When you can connect from other systems (did you use the same server name and port number 587 there?), it must be a firewall that is blocking requests by the source IP (IP is black listed or not white listed).
40.101.88.18 belongs to Microsoft. Which SMTP server name have you specified?
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My first guess was also that the problem is in our firewall, but I only asked our admin about a port being blocked. I will have to ask again about a possible black/white listing. Thanks for that suggestion.
As for the SMTP server, per MickeySoft's instructions I use smtp.office365.com and port 587 or 25. I suppose that address has its own autodiscover protocol. nslookup gives me the specific smtp server name outlook-emeaeast3.office365.com and 9 different IP addresses.
What I have been wondering about is, how MS Outlook contacts exchange online. Why is it not having any problem connecting?
My advice is free, and you may get what you paid for.
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The error message indicates that a target / remote side refuses the connection. This is usually a system behind the first router (the first router should send a different message when he blocks outgoing attempts). I don't think that MS is blocking accesses from your company. Because it works on other sites, it is most probably sourced somewhere in your company network or your companies internet provider.
Many companies block outgoing SMTP except for white listed source IPs (e.g. only a local forwarding SMTP server is allowed to talk SMTP to the net).
The network admin in your company is the responsible person to contact. Even if he tells you that there are no filter rules, he might help better because he should know the toplogy of the company network.
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So you have the correct SMTP Server - smtp.office365.com and correct Port - 587, what Encryption are you using?
Microsoft says to use TLS and I bet Outlook is set to use it but have you set it in your code?
Michael Martin
Australia
"I controlled my laughter and simple said "No,I am very busy,so I can't write any code for you". The moment they heard this all the smiling face turned into a sad looking face and one of them farted. So I had to leave the place as soon as possible."
- Mr.Prakash One Fine Saturday. 24/04/2004
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Hi Michael,
Thanks for your response. My apologies, I posted about this problem on another forum as well, and forgot to update this one.
As it turns out, our firewall wasn't blocking any ports, it was just not allowing other SMTP traffic than specified, and nothing was specified.
Anyway my code was good, including TLS, so the question remains, how come Outlook was not blocked by our firewall, when my code was.
Regards,
Johan
My advice is free, and you may get what you paid for.
modified 1-Mar-18 4:12am.
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I hope I am in the right forum regarding the question with Internet Explorer and Proxy configuration. If not kindly let me know.
For the past few days I am witnessing the following with my IE 11 (and hence Chrome).
1) Automatically Detect Settings (checked) and a Proxy Server Entered in LAN Settings. Not able to use Internet in Corporate Network.
2) Resolution for (1) above. Uncheck Automatically Detect Settings.
3) At home, Both Automatically Detect Settings and Proxy Server to be Unchecked again to use my WiFi router.
Over the past weeks I never remember going through these manual process. Both used to be on and I was able to seamlessly use the Internet both at home and at work. What has changed over the past few days? Any Windows Update is causing IE to break?
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Years ago, when I was eking out a subsistence living fixing and maintaining PCs and networks, every new version of Windows was accompanied by a new, grossly overpriced set of manuals called Resource Kits. I dutifully bought them, since it was impossible to learn how to fully support the product without all that insider information. I haven't looked for such a beast in a while, but I could really use one for Windows 10. I have yet to find anything equal to the old Resource Kits, but admins must use something equivalent to survive. What took the place of this invaluable reference?
Will Rogers never met me.
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Hi all,
INTRODUCTION
I'm thinking about a portable solution with a single board PC (lattepanda[^] or similar).
The device can't include batteries and must be connected to all the peripherals and power using a special cable.
The problem is that the user will unplug it without shutting the Operating System down properly.
Given this will happen often (twice per day probably) I need to solve it and I was thinking on using FBWF[^]...
QUESTION
If I activate the FBWF and protect all the folders of the hard disk could I be sure that the computer would start always without problems and without damaging any file?
Any experience using this on windows 10?
The help file says it will be OK, and I used it with WES7 and it worked but it was an industrial computer and I wanted to double check it before proceeding with the project.
Thank you all! 
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If you yank the drive out before the write is complete, safe or not, you'll be missing data. If the device is "ejectable" in any form, you could try that. If it supports unmounting, that would work too. Any way - even if it is a SSD-drive in RAID - if you yank it out before the led stops flickering, you're in trouble.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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So... what is FBWF useful for?
I was thinking on using it precisely to avoid that...
Thank you!
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Joan M wrote: So... what is FBWF useful for?
See MSDN[^].
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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Yes, I can see it, but then I don't understand it:
File-Based Write Filter (FBWF) enables redirection of all changes made to a protected volume to an in-memory overlay. This provides system designers with the option of discarding all changes made to a system in a manner that is transparent to user applications.
As far as I understand it I could set all the windows files to be protected and then no problem would happen...
I understand it to be like a steadystate but for newer Oses...
Am I understanding it wrong?
Thank you very much Eddy!
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Joan M wrote:
As far as I understand it I could set all the windows files to be protected and then no problem would happen...
How about Windows-updates?
Joan M wrote: Am I understanding it wrong?
Dunno; sounds to me like some sort of buffer. If the disc is not yanked out, and people simply forget to shut down, then it may result in a file being corrupted if the write doesn't complete. If the system has nothing to "write" and is merely shutting down, nothing gets corrupted - you simply loose what is in memory.
I don't know how this specific class could help.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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Eddy Vluggen wrote: How about Windows-updates?
A lot of industrial systems around are even not connected to the Internet or network and used to control machines... so no need to use updates...
In most cases, though, computers are placed inside the electrical cabinets then I used some kind of UPS systems to keep them running while shutting them down.
In this case weight is a very important factor and a UPS is completely impossible. and the portable computer will never connect to anywhere except from machine computers that will also never be connected to anywhere...
I understand FBWF as it getting a copy of the files the OS uses, never touching the original files, therefore the original files can't be corrupted... 
Let's see if someone here has used it extensively and knows exactly how it works...
thank you very much for your help Eddy!
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Joan M wrote:
I understand FBWF as it getting a copy of the files the OS uses, never touching the original files, therefore the original files can't be corrupted...
The OS is mostly "reading"; there are Linux-versions that can be run from USB and mount completely in memory - turn the PC of and it is gone. If you only have the OS on the key, and all other important info somewhere else, then a non-working machine (in case of corruption) could be "fixed" by plugging in a new bootable usb-key.
Also, you won't corrupt files by reading them; it is interrupting a write-operation that is dangerous and can cause corruption.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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Joan M wrote: The problem is that the user will unplug it without shutting the Operating System down properly.
Reading the thread below I want to repeat what was already said...there is NO way to protect it as described.
Best you could do would be to re-engineer/re-spec the device so it has a onboard battery that has sufficient juice to allow an automatic shutdown once the real power is interrupted.
The alternative to that is that users that do not do it property are disciplined up to including being fired. After a while you will only have users that always do it "properly".
If it was me I would propose both solutions to management and let them decide. Option one is of course more expensive and requires quite a bit more code. And code that is quite complicated also.
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I have a group in Lotus notes where members are not receiving their emails?
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there are several developers using same server under same credentials (very convenient) under rdp.
I want to be able to give and revoke access w/o changing those creds (iis apps running etc)
I understand from research that ipsec can solve that.
We install it with different keys on each programmer’s computer and configure server firewall/cisco gateway To allow rdp over ipsec only
So 1. We know whose session it is and 2. If somebody leaves we just disable his or her access.
So single account on server is ok as long as we control who gets there
1. please confirm my findings
2. please give me a pointer to some article where I can find
step by step high level instructions say we have 10 user computers and data center network like server1, server2
What do we do to implement ipsec and force rdp over ipsec only!
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will it work as is after upgrade
if not what to do
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You could try looking up the product on MSDN, go the the correct version and read the "what's new" section.
You could also install it on another server and do the update there first; would give you a reasonable idea of what to expect. No, you can use trial-versions for that.
Let us know how it went 
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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