I am hot desking in the same office as a potential competitor & would be using the same wifi. The building owner runs the competitor company.

My question is, can the wifi administrator see mail I have sent through outlook (via Google apps) when using my personal machine? Concerned about email content but also the actual recipients email address as would rather they did not know the companies I was working with. Would the recipient email be visible?

If yes, is there anyway to protect myself?


Assuming the "WiFi administrator" only has access to the network, and isn't actively trying to attack you, I think your email is safe if properly configured.

Because they control the network, they can see all the traffic that crosses it. This would be a problem for unencrypted connections (e.g. HTTP traffic, or unencrypted POP or SMTP traffic).

However, the Google Apps Sync for Microsoft Outlook plugin specifies port 443 needs to be open for communications, and port 80 needs to be open so it can receive a certificate revocation list. This strongly indicates that TLS or some similar form of certificate based encryption is in use.

If you're using IMAP/POP/SMTP settings instead, the help page indicates that they can be configured to use encryption.

Incoming Mail (IMAP) Server - Requires SSL

Port: 993
Requires SSL:Yes

Outgoing Mail (SMTP) Server - Requires TLS

Port: 465 or 587
Requires SSL: Yes
Requires authentication: Yes
Use same settings as incoming mail server

Therefore, if you have configured Outlook properly on your computers, the WiFi administrator won't be able to see your email content or recipients. They can only see encrypted blobs (essentially random noise).


Short answer: They could.

Any information you send through their equipment they can intercept and read. If you send it plaintext, then it would be trivial for them to retrieve it plaintext since they control the flow of information.

To prevent this, see if your email provider supports SSL or (preferably) TLS on their SMTP server. This will encrypt the connection going out and should prevent anybody from intercepting your messages.

An encrypted connection through a VPN or proxy could also serve a similar purpose, if you happen to be using such a connection for your own workplace.


if the wifi administrator can sniff your network trafic. yes he can. if he can see your email. It depend on the way you connect to your email server. If it trough a secure channel the administor will only see encrpyted network packet.

you'll have to check if you're using imaps and smtps.Not sure but i think gmail force secure connection.


Use an encrypted connection on any traffic sent on the Wifi: Google Apps offers this out of the box.

Alternatively, use a VPN.


To add to @Thebluefish's answer (I can't comment):

They can intercept the information from you and read everything. The best way would be to implement a Man-In-The-Middle attack. To imagine this look at the following scenario:

  1. You send an email to the server (Encryted)
  2. The wifi administrator pretends to be the server (shows certificate) and he decrypts your message.
  3. He then pretends to be the client, encrypts the information and sends it to the real server.

With all this said the only need he has in order to pull this of is for the security certificate he presents to you to be trusted by your machine or you as a user.

Image showing a simple diagram of MITM attack

More detailed image explaining the process

This picture shows how the process happens in more technical terms.

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