EMail FAQ
- Can I use IMAP or POP3 to access my email?
- What hostnames should I use for my email configuration?
- Why can't I use the department's mail server for sending outbound email from outside the department (gives error "Relaying Denied")?
- I've been spammed, what do I do?
- How come I don't get messages sent to 'building@lists.cs.princeton.edu'?
- Every time I start my mail client, I get a warning that the mail server's SSL certificate is not trusted and asking if I want to trust it. Once I answer "Yes" everything proceeds normally. Is there anything I can do to make this stop?
- Outlook reports "Your outgoing (SMTP) server does not support SSL-secured connections. If SSL-secured connections have worked in the past, contact your server administrator or Internet service provider (ISP)."
- I am unable to receive email from some people, but others can send me email without problems. What is going on?
- The mail I get from some sites (such as gmail.com) seems to be delayed by several minutes or sometimes up to a couple of days. Why?
- I am unable to receive any email. Why not?
- I hear there's a quota on my email. What is my current usage?
- Why do I get so many email messages with the subject "Returned mail: User unknown" (or similar)?
- My email client suddenly can't connect to the server, even though it was working before and I'm sure I'm typing the right password. Logging in to CS Webmail reports that my account is in "Maintenance Mode". What's going on?
- How can I forward all of my CS email to another address?
- How can I set up a vacation email auto-responder?
- How can I set up forwarding of my Princeton (OIT) email to another address?
Yes, IMAP and POP3 access is available for your email. See the Email section of the CS Guide for more information.
This is important first of all because these names will persist across mail server upgrades. If we change mail server hardware, these DNS names will remain. It is also important in the case of SSL IMAP and POP3 because if you do not use these names specifically then your mail reader will probably complain about a certificate not having the proper identification.
- Outbound Mail - 'smtp.cs.princeton.edu'
- Inbound Mail (IMAP) - 'imap.cs.princeton.edu'
- Inbound Mail (POP3) - 'pop.cs.princeton.edu'
For security reasons, all e-mail submissions must use SSL and authenticate to the server in order to send email to recipients outside the department.
Most modern email clients are capable of SMTP Authentication and SSL. Configuration details will vary by client, but the credentials you need will be your Unix username and password, the same as for reading email using Webmail, IMAP, or POP.
We may be limited in what we can do to help you, but the first step would be to email us the message with all headers intact. We might be able to block the sender or host at our mail server but it depends on several variables.
If you are not receiving the messages, it may be because you are not subscribed to the building mailing list.
For eligibility and subscription information, follow this link.
This FAQ is outdated. If you are seeing this error for CS Email servers, you should be concerned and contact CS Staff.
Many ISPs block or intercept connections on port 25 in order to attempt to reduce spam coming from their networks. The proper configuration is to change the Outgoing (SMTP) port number in your client to 587. This should, in most cases, allow you to connect directly to our server so that TLS and authentication will work as expected.
It's possible that the messages in question are being delayed or rejected by one of the department's anti-spam filters.
The explanation for this has grown beyond a simple FAQ entry, and so has been moved to its own CS Guide page here: Proofpoint and Princeton CS Email.
At this time, CS Staff is not aware of any situations that would be expected to cause such delays. This FAQ was written during a time when certain mail filters often did cause delays.
If some of your mail is suffering undue delay, please send the complete headers of such a message to CS Staff so that we can attempt to identify the issue.
There are a few possibilities for why you may not be able to receive email. Here are some things to check:
- Are you over quota?
- Is anyone else receiving email? - If you have verified that you are using IMAP or POP properly, and you are confident that you are not over quota, then it is possible that there is a general email outage. Check the CS Guide main page for scheduled downtime or other information.
Please see the Email Quota page.
The subject of these bounced messages is often similar to:
The body of the message may be similar to the following:
- Returned mail: User unknown
- Returned mail: see transcript for details
- Returned mail: delivery problems encountered
- Mail Delivery Problem
- Delivery Status Notification
----- The following addresses had permanent fatal errors -----
< username@email!address.com > (reason: 550 5.1.1 < username@email!address.com >... User unknown)
In the above example, username@email!address.com was an address that is no longer in use, so the system at email!address.com sent a message explaining that the email was not received.
As an analogy, this is similar to someone going to the post office, sending a letter to a non-existent location and putting your address as the senders. When the post office finds out that the letter cannot be delivered to the intended recipient, the letter will be returned to you, since your address was listed as the sender.
There are various reasons why these types of emails are coming into your Inbox but the most likely reasons are:
1. Someone has "spoofed" your email address, making it look like the email originally came from you. This is a popular tactic that spammers use to send their spam emails. If any of the spam messages are sent to an address that doesn't exist, the email is bounced back to your account, since the spammer made it appear as though the email originated from you. In these cases, there is not much you can do to completely eliminate the problem because the spammer has simply guessed your email address and has inserted it into the From: field, making it look like these emails are coming from you.
2. Another possible reason for getting these emails is that a virus and/or worm may have infected your system. Make sure to update your anti-virus and firewall software and run a full system scan. If you do not have an anti-virus or firewall program installed on your computer, you can take advantage of the suggested software provided by the Office of Technology (visit https://princeton.service-now.com/service?sys_id=3308&id=kb_article for more information).
3. If you're certain that your PC does not have a virus, the more likely scenario is that an email virus and/or worm may have infected one or more of your associates' computers, and these people probably have your email address in their address book. The virus tries to spread itself by sending messages to many other users, using the address book of the infected computer. The virus/worm will often use a false address (yours) as the Reply-to: or From: address. If any of the messages that the virus sends bounce back, you will receive that message.
Our email servers perform backups nightly starting at 01:00 and running until they complete. The end time varies based on which accounts are being backed up, as each account is backed up once per week. As each account is backed-up, it is temporarily brought offline so access is suspended. The actual downtime for each account depends on the amount of data to be backed-up, and can vary from a few minutes to a couple of hours for the largest accounts. By performing backups in an offline mode, we ensure maximum integrity of the backed-up data.
University Position Paper on automatic email forwarding
Before making this change, please note that forwarding email is strongly discouraged. Due to the evolution of how internet email works, forwarding email often results in it being classified as spam regardless of its content. Email forwarding is at your own risk. If your preferred provider offers the option, it is preferable to have the external provider access your CS email using POP3 or IMAP and present it in your preferred mailbox. Make sure to enable 2FA and Application Passcodes on your Zimbra account before configuring such an arrangement.
To forward all of your incoming email to another address, login to the Webmail system using your Unix username and password:
https://webmail.cs.princeton.edu/
Once logged in, click the "Preferences" tab at the top of the screen. Within this tab, you can change many details about your email delivery and presentation. For email forwarding, click on the "Mail" section within Preferences, scroll down to the "Receiving Messages" section and find "Forward a copy to". Enter your forwarding address in the text box, and optionally check the "Don't keep a local copy of messages" box if you wish the email to only be forwarded rather than also delivering it locally.
To start with, login to the Webmail system using your Unix username and password:
https://webmail.cs.princeton.edu/
Once logged in, click the "Preferences" tab at the top of the screen. Within this tab, you can change many details about your email delivery and presentation. For a vacation message, click on the "Out of Office" section in the left-side navigation pane. Check the "Send auto-reply message" option, and set your auto-response message. You can also optionally set start and stop dates for the message. This will allow you to setup a vacation message before your departure that only begins sending auto-responses once your vacation starts, and stops automatically at the end date.
University Position Paper on automatic email forwarding
Before making this change, please note that forwarding email is no longer recommended. Due to the evolution of how internet email works, forwarding email often results in it being classified as spam regardless of its content. Email forwarding is at your own risk.
If you are faculty/staff using OIT's Exchange service, use the following link:
OIT KnowledgeBase: Exchange: How to forward your Princeton e-mail to another address