how to confirm email source

Question

I send an email from my smtp server, for example, setting `From` to anyemail@anydomain.com. The recipient will think that email comes from `anydomain`. How to confirm the email source?

Accepted Answer

There are several approaches to dealing with email forgery:

- Use PGP or SSL signed certificates

- Use SPF

- check the `Received` headers (although this isn't reliable)

- reply back to the sender and ask if they actually sent it. If you know the sender, maybe ask them in person or over the phone.

The main thing to realise is that the From: address isn't any form of guarantee about the originator of a message.

Edit: okay I now understand that you're just trying to tag the mail message somehow so that you can recognise which server generated it (in a non-secure way). Here's how using .NET's MailMessage:

```
System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage();
msg.Headers.Add("X-Is-Development", "true");
```

how to confirm email source

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