networking - Can outgoing emails from a webmail provider be blocked using network management software?

07
2014-07
  • Vinayak

    This is probably a ridiculous question, but is it possible to only restrict outgoing email sent from free webmail providers (Gmail, Yahoo, etc.) in a corporate network using network management software?

    This is assuming users do not have access to a VPN service to bypass network restrictions and that email is accessed solely using a web browser.

    • Answers
  • F2nd

    For web-interfaces users only need HTTP proxy to sent e-mails, so it would be impossible to block specific sites without traffic inspection.

    Also, inspection of HTTPS traffic require performing some kind of MiTM - installing on user's machines your root CA and signing with it wildcard cert for you [transparent] proxy server, which will decrypt and analyze all passing HTTPS data.

    So simplest way to prevent inexperienced users from using external e-mail services may be DNS blocking - install DNS caching server on your network, limit external requests on UDP and TCP ports 53 so only this server can do so and add DNS records for undesired domain's that point to some other IP, i.e. 127.0.0.1

    This kind of blocking can be bypassed quite easy. It's far better to provide handy internal mail service and persuade everybody to use only it for work letters.


    • Related Question

    download/export emails from webmail
  • misterjinx

    I'm just switching my hosts and I want to move the emails from my accounts too. In order to have my current emails on the new host I want to download/export them and to import at the other host. In order to do this I use one of the webmail (squirrelmail, roundcube, horde) clients available on my current host.

    The problem is that except for roundcube, I don't see any download/export option available. And in roundcube I can only select one email at a time and download it as eml.

    My question is how do I export/download all the emails from one account and import them at the new host? I know this is possible because I remember doing this some time ago using squirrelmail, but I can't find anything related to this now.

    Thank you.


    • Related Answers
  • NReilingh

    You'll need to be able to access your email through an IMAP connection in order to do this. Unless there is a specific archival download option offered from the webmail clients (and I'm not familiar with any but squirrelmail), that's your only option AFAIK. If the provider only offers POP, then at least you can archive your messages, but you won't be able to import them to the new server unless it supports IMAP.

    Find out the connection settings from your provider and set up Thunderbird or the client of your choice. (I do this in Apple Mail routinely.) With IMAP, just copy the messages from the folder on your server to a local one on the client, then reconfigure the client for the new server and then copy them back.

    With POP it's a little weirder since that protocol is only one-way. You may need to do some tweaking on the client to get it to download all of your old messages, but once you do you'll at least have a local archive.