PSCS Wiki

Seeing where a message came from

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Seeing where a message came from Sometimes you need to check to see where a message really came from. The 'From:' email address is easily forged, so that cannot be relied upon. The first thing you have to do is to get the full message headers. These may look daunting, but are very useful for problem diagnosis.

How to send a fax by email using the VPOP3 FaxServer

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to send a fax by email using the VPOP3 FaxServer VPOP3 2.1.0 and later together with the VPOP3 FaxServer software allows you to send specially crafted emails to VPOP3 to have them sent as faxes. To do this, send an email to fax@ . The email subject will be the subject of the fax used on the fax cover page. The email should be in plain text (not

421 4.3.2 VPOP3 Too many connections from your IP address - try later

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

421 4.3.2 VPOP3 Too many connections from your IP address - try later If you see this error message when you are sending messages, then it means that VPOP3 has detected too many simultaneous connections from your IP address. This would usually happen if the sender is another mail server as they can make many simultaneous connections when there are lots of messages to send. The error code that VPOP3 gives means that the sender should try sending the messages later, so it should be possible to e…

How to create a Mail Sender

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to create a Mail Sender In VPOP3 a Mail Sender tells VPOP3 how to send mail out to another mail server, usually for sending mail across the Internet. To create a mail sender, go to the VPOP3 Settings, then Mail Connectors. In the Mail Senders section on the left, choose

French Webmail Language File

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

French Webmail Language File Copy/paste the text below to a file 'french.lng' or 'francais.lng' in the VPOP3 directory. (French users, feel free to update/correct the text below) #login page logintitle=VPOP3 Login webadminlogin=web admin login webmaillogin=web mail login enterusername=You must specify your VPOP3 username here bookmarksnotsupported=I'm sorry, but your web browser does not support this function. You will have to add this page to your bookmarks manually. loginfailed=Login Faile…

German Webmail Language Page

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

German Webmail Language Page Copy/paste the text below to a file 'german.lng' in the VPOP3 directory. (German users, feel free to update/correct the text below) #login page logintitle=VPOP3 Login webadminlogin=web admin login webmaillogin=Webmail Anmeldung enterusername=Sie müssen einen Benutzernamen angeben bookmarksnotsupported=I'm sorry, but your web browser does not support this function. You will have to add this page to your bookmarks manually. loginfailed=Anmeldung fehlgeschlagen …

How to remove messages from the outbound queue

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to remove messages from the outbound queue To delete messages from the VPOP3 'OutQueue': * log into the VPOP3 settings * go to the Users page * click on the OutQueue entry in the accounts list. This will show you a list of all the messages waiting to be sent by VPOP3

Backscatter

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Backscatter In email, “backscatter” is the term used if you send bounce messages back to spam messages. As most spam messages use forged email addresses, then the bounce messages will go to an innocent person, who will find them very annoying. Stopping VPOP3 from sending Backscatter

Configure SRS

Anonymous (anonymous@undisclosed.example.com) — 2025-08-18T15:28:11+00:00

Configure SRS In VPOP3 8.8 and later, you can use Lua scripting to implement 'SRS' (Sender Rewriting Scheme') in VPOP3 This involves adding a couple of functions to rewrite outgoing return paths in 'relayout.lua' or 'mxout.lua' as appropriate and a couple of functions to redirect rewritten bounce message recipients in 'smtpsvr.lua'

Error Messages

Anonymous (anonymous@undisclosed.example.com) — 2025-10-06T15:21:37+00:00

Error Messages This is the place to look if you are trying to trouble shoot a problem and you have received or have access to a specific error message or error code. If instead your problem is that something you think is set up correctly is not working then the best place to look would be the

Not Working As Expected

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Not Working As Expected This is the page to come to if you think you've set something up correctly but it isn't doing what you think it should be doing. If you're getting an error message or some other concrete indication that something has actually 'gone wrong' then the

Sending mail from different email addresses or domains

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sending mail from different email addresses or domains VPOP3 does not (by default) place any restrictions on which email addresses or domains you can send mail from. However, there may be external restrictions on which email addresses/domains you can send from. For instance, if you send mail through your ISP's mail server, they may only allow you to send mail from specific addresses, or the domain you send mail from may have a sender policy defined, such as

Spamfilter Whitelist & Blacklist

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Spamfilter Whitelist & Blacklist The VPOP3 spamfilter has a whitelist and a blacklist for sender addresses. It also has a whitelist and blacklist for words/phrases. You can view these lists in the VPOP3 settings by going to Settings -> Spamfilter ->

550/553 Not Permitted error from BT Internet's mail servers

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

550/553 Not Permitted error from BT Internet's mail servers BT Internet's mail servers only allow messages to be sent from 'approved' email addresses. If you try to send messages from other addresses BT's mail servers may return a '550 Not Permitted' error, a '553' error, or may silently discard the message depending on what their server feels like doing today.

Copy Outgoing mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Copy Outgoing mail Sometimes people need to copy outgoing mail for various reasons. There are several ways of doing this in VPOP3 depending on your exact requirements: * Message Monitoring - this copies all outgoing, incoming and/or internal mail sent by/to specific users to another specific user

Initial Configuration Tasks

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Initial Configuration Tasks After installing VPOP3, you will need to get into the VPOP3 settings. The easiest way of doing this is to find the VPOP3 Status Monitor in the Windows task tray. Right-click this icon, and choose 'VPOP3 Settings'. (If that doesn't work, see this article to troubleshoot Status Monitor problems). Alternatively, on the VPOP3 PC, you can go to Start

"How To" Articles

Anonymous (anonymous@undisclosed.example.com) — 2026-03-18T20:20:50+00:00

"How To" Articles Installation/Upgrades * Download VPOP3 * Install VPOP3 * Move VPOP3 * Upgrade VPOP3 * Upgrade VPOP3 to version 5.x or 6.x from version 4 or earlier * Upgrade VPOP3 to version 7.x from version 6 or earlier * Upgrade VPOP3 to version 8.x from version 7 or earlier * Upgrade VPOP3 to version 9 or later from version 7 or 8 * Performance Requirements * Installation Checklist General Configuration * Initial Configuration * Users * Add an Alias * Create…

Restricting the number of recipients sent to

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Restricting the number of recipients sent to Some ISPs set restrictions on the number of recipients that you are allowed to send in a certain time period, eg 50 messages per hour, or the number of recipients that you are allowed to send per message or per connection.

Route MX Sent (Direct) Outbound Mail Through Your ISP

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Route MX Sent (Direct) Outbound Mail Through Your ISP Some mail providers (for example Hotmail, AOL and GMail) will reject mail sent from servers running on dynamic IP addresses. It is possible to route such mail through your ISP's relay server whilst still sending most mail direct to the recipient server using MX

Sender Domain Must Resolve

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sender Domain Must Resolve If you receive an 'SMTP Client Error' something like: 451 (user@domain.com) Sender Domain Must Resolve this means that the ISP's mail server cannot find the domain.com part of the email address. Often this means that the FROM address of the message is invalid, or that the

Sender Policy Framework / SPF

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sender Policy Framework / SPF SPF is a system used to tell mail servers which IP addresses can send mail from which domains. It is designed to reduce 'spoofing' of email addresses. For instance, if you receive an email message from your bank, your mail software can check that it came from an IP address authorised to send mail from your bank, and treat the message with suspicion if it didn't come from an authorised IP address.

Sending mail through your Gmail account

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Sending mail through your Gmail account According to Google, the settings for sending mail through Gmail are: Outgoing Mail (SMTP) Server - requires TLS or SSL: smtp.gmail.com (use authentication) Use Authentication: Yes Port for TLS/STARTTLS: 587 Port for SSL: 465

When sending mail, VPOP3 adds 'PRVS=...' to the sender address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

When sending mail, VPOP3 adds 'PRVS=...' to the sender address This is because VPOP3 version 5 and later support BATV. BATV helps to eliminate 'backscatter spam', where someone else sends spam pretending to be from you, and then you receive all the bounce messages from those messages. BATV encodes the sender address in a special way so that VPOP3 can detect that a bounce message is in response to a message that you actually sent.

550 5.7.1 Relaying not allowed! Bad sender IP address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

550 5.7.1 Relaying not allowed! Bad sender IP address This SMTP error message means that the computer which is sending the message is not permitted to send outgoing messages based on the VPOP3 SMTP Service's Access Restrictions. This is probably because someone is trying to send messages from outside your local network, and you have not configured VPOP3 to allow this. You have to be careful when allowing this, because you may configure VPOP3 to be an open-relay, which is a

Attachments have been removed or renamed

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Attachments have been removed or renamed If you have received an email and one or more of its attachments have been removed or renamed, it might be a result of Attachment Filtering. You can inspect the filtering rules by going to Administration Settings -> Settings ->

Configure Email Signatures

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Configure Email Signatures * Global Signatures * Personal Signatures * Webmail Signatures Notes When creating a signature it is generally best to keep it as short as possible. Disclaimers & confidentiality notices in emails are generally regarded as having little or no legal significance, so lengthy signatures just use up bandwidth.

Controlling VPOP3 via Email

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Controlling VPOP3 via Email You can control certain aspects of VPOP3 by sending emails to 'mailer_daemon@' The subject line must be one of the lines below: * Set Assistant * Query Assistant * Password * Set Forwarding * Query Forwarding

Data stream contained NUL character

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Data stream contained NUL character Description of the problem NUL characters (bytes with value 0) are not allowed in email messages and should not be transmitted over POP3, SMTP or IMAP4 except in certain circumstances. If an attachment contains such a byte it must be encoded using

Delete OutQueue messages directly from the database

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Delete OutQueue messages directly from the database If there is an extremely large number of messages (eg hundreds of thousands) in the VPOP3 OutQueue, then it may take a very long time for VPOP3 v5 and later to start as it check the message database tables for consistency during initialisation.

Download Rules

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Download Rules Download rules are applied to messages downloaded using a POP3 mail collector. To configure the rules, go to the VPOP3 settings, then Mail Connectors -> Mail Collectors -> POP3 General. There is an Edit Download Rules button which brings up the download rule editor. To tell this mail collector to use the download rules, ensure that the

Error message after sending RCPTTO: - error 0 - text 550 5.7.1 Relaying not allowed! Bad sender IP address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Error message after sending RCPTTO: - error 0 - text 550 5.7.1 Relaying not allowed! Bad sender IP address If you get this error message from within Webmail, then it usually means that the SMTP service access restrictions are blocking Webmail from sending mail.

How to filter attachments

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to filter attachments VPOP3 can filter attachments in several ways. The most general is to use the Settings -> Attachment Processing -> Filtering tab as described below. VPOP3 can also filter attachments using the content/spam filter, or by using an integrated virus scanner.

How to Forward Messages to an External Address

Anonymous (anonymous@undisclosed.example.com) — 2025-08-18T15:13:06+00:00

How to Forward Messages to an External Address There are two possible methods to forward messages to an external address: * Use this method if it is for a person who might want to receive their email whilst in the office and/or get the mail sent to an external address.

Forwarded Emails Not Arriving

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Forwarded Emails Not Arriving If you are having problems having VPOP3 forward incoming messages to an external address, but sending messages directly to that address works OK, and forwarding internal messages to that address works OK, then the problem may be the SMTP return address which VPOP3 is using.

The ISP needs SMTP Authentication

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

The ISP needs SMTP Authentication If your ISP needs you to use SMTP authentication when sending mail to them, then you just need to tell VPOP3 to use authentication when sending. Click the Mail Connectors button at the top of the page, then click on the relevant

How to limit size of sent mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

How to limit size of sent mail There are several ways to limit the size of mail which can be sent * Limit the size of mail accepted by the SMTP component of VPOP3 * Limit the size sent for a particular user * Limit size based on 'rules' * Limit size based on

Make VPOP3 retry outgoing messages immediately

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Make VPOP3 retry outgoing messages immediately If VPOP3 has a temporary problem sending a message it will retry it later. When it will retry it depends on how many times it has already tried to send it, and is based on the 'Sender Retry' setting in the Mail Connectors

MX Send Warning - .....

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

MX Send Warning - ..... If you see the text 'MX Send Warning - ' in the VPOP3 status monitor, that means that VPOP3 is trying to send a message to another mail server using the MX send method (direct to the recipient's mail server) and

Out of Disk Space When Sending Mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Out of Disk Space When Sending Mail The first thing you should do is check that there is enough free disk space on the disk where VPOP3 is installed. VPOP3 requires a certain amount of free space before it will allow new messages to be sent, so the disk might not be totally full, but VPOP3 will still report that there is insufficient disk space when you try to send a new message. This buffer zone is designed to help prevent the disk totally filling up, which can cause lots of bigger problems!

Outgoing Mail

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Outgoing Mail * Create a Mail Sender * Route MX Sent (Direct) Outbound Mail Through Your ISP's Relay Server * ISP needs SSL connection * ISP needs you to connect on port 587 * ISP needs SMTP Authentication * ISP Needs POP3 Before SMTP Authentication * Limit size of sent mail * Require SMTP Authentication when users send mail to VPOP3 * Sending different users' mail through different ISP relay accounts * Restricting number of messages sent (per hour etc) * Restricting numbe…

Problems sending messages to spam@

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Problems sending messages to spam@ If a VPOP3 user forwards a message to spam@, then the VPOP3 spam filter will train itself that that message was spam. If, when you forward the message, you get an error message like: Subject: Mail Delivery Failure Delivery Failure Report. The following message was incorrectly addressed. Recipient: "spam" is unrecognised.

Spam Quarantine

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Spam Quarantine By default, when the VPOP3 spam filter detects a message as being spam, it will go to the user's quarantine. Users can release messages from the quarantine by going to their webmail page and selecting the message from the quarantine list there.

Redirect message for a user if a sender is a particular email address

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Redirect message for a user if a sender is a particular email address Say you want messages addressed to 'user1' to be redirected to 'user2' if they came from customer@domain.com This is an unusual requirement, so there is no way to do it in VPOP3.

Require SMTP Authentication

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Require SMTP Authentication There are some situations where VPOP3 needs to know who is sending mail. This may be if you have VPOP3 configured to behave differently depending on who is sending messages - eg if you have different message size limits depending on the sender, or if you have message monitoring configured for certain users, or you don't want certain people to be able to send mail at all.

Restricting the number of messages sent

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Restricting the number of messages sent Some ISPs set restrictions on the number of messages that you are allowed to send in a certain time period, eg 50 messages per hour, or the number of messages that you are allowed to send per connection. Restriction of messages per connection

Anonymous (anonymous@undisclosed.example.com) — 2026-03-26T13:15:40+00:00

Signing outgoing mail with DKIM

Anonymous (anonymous@undisclosed.example.com) — 2020-07-22T10:32:40+00:00

Signing outgoing mail with DKIM DKIM, also known as DomainKeys Identified Mail, is a form of email authentication that digitally signs emails to prove that they were sent from authorized domains and aren't fake emails. Companies like Google and Yahoo use DKIM to sign their emails and it is becoming ever more popular.

Spam filter not working

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Spam filter not working If the VPOP3 spam filter appears not to be working at all, the first thing to do is to look at the message headers of an incoming message to see if the spam filter is being run at all. Check to see if a header line beginning with X-VPOP3-Spam

Training the VPOP3 Spam Filter

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Training the VPOP3 Spam Filter The VPOP3 spam filter has a couple of mechanisms which can be used to 'train' it to distinguish between spam and not-spam. Bayesian Filter The Bayesian filter this looks at words in messages sent and received and their probabilities of being contained in spam and not-spam, and works out an overall probability of the message being spam or not-spam based on the combination of those probabilities.

Transmission Receipt Message

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Transmission Receipt Message This is not an error message, but we are listing it here because it confuses some people. VPOP3 sends a 'Transmission Receipt' when a message is sent out, and it contains a header asking for the receipt. The default configuration is that it will send the transmission receipt if the sender asks for a read receipt.

Use Download Rules for incoming POP3 message filtering

Anonymous (anonymous@undisclosed.example.com) — 2018-11-14T10:45:49+00:00

Use Download Rules for incoming POP3 message filtering If you have VPOP3 retrieving messages from a POP3 account on an ISP, then you can use Download Rules to do basic filtering on incoming messages. (If you have incoming SMTP, then use SMTP Rules instead) Download rules cannot perform all mail filtering tasks. For more features,