Outgoing Spam Monitor (OSM) is a tool that can be used to monitor and prevent email from being sent from your server that is not destined for a local user. It can be run in passive or active modes. Passive (monitor) mode uses the exim queue number feature to monitor all outgoing emails, it records the IP address, sender and recipient details of emails sent from the server. Active mode uses the exim address_rewrite feature to block outgoing email that does not match specific criteria. This is a more advanced form of blocking and could potentially break legitimate mail if mis configured so we recommend you test it thoroughly before putting it into production.’
Outgoing Spam Monitor (OSM)
Outgoing Spam Monitor (OSM)
OSM can be used to monitor and prevent email from being sent from your server that is not destined for a local user. OSM can also be run in passive or active modes. In passive mode OSM waits until it receives an incoming SMTP connection request before responding with a rejection message.
In active mode, the server responds immediately with a rejection message whenever it receives an incoming SMTP connection request; this prevents unwanted messages from being sent while they are being processed by your system’s Anti-Spam software
OSM can be used to monitor and prevent email from being sent from your server that is not destined for a local user. It can be run in passive or active modes.
OSM can be used to monitor and prevent email from being sent from your server that is not destined for a local user. It can be run in passive or active modes.
Passive mode uses the exim queue number feature to monitor all outgoing emails, so you don’t have to worry about installing additional software on your email server.
Active mode will listen for messages from OSM on port 25 (SMTP) and forward them into your own SMTP server if they match any criteria you set up beforehand.
Passive (monitor) mode uses the exim queue number feature to monitor all outgoing emails, it records the IP address, sender and recipient details of emails sent from the server.
Passive mode uses the exim queue number feature to monitor all outgoing emails, it records the IP address, sender and recipient details of emails sent from the server.
The passive mode requires no configuration changes to exim and can be run alongside active mode if required.
Active mode uses the exim address_rewrite feature to block outgoing email that does not match specific criteria. This is a more advanced form of blocking and could potentially break legitimate mail if mis configured so we recommend you test it thoroughly before putting it into production.
Active mode uses the exim address_rewrite feature to block outgoing email that does not match specific criteria. This is a more advanced form of blocking and could potentially break legitimate mail if mis configured so we recommend you test it thoroughly before putting it into production.
The main benefits of active mode are:
- It can be used to block specific email addresses or domains (for example, if the sender’s domain is known malware).
- It can also be used to block all email from a specific IP address (for example, if your company has blocked all outgoing connections from China).
Both monitor and active modes only monitor emails sent through exim, they do not stop outgoing mail being sent through smtp clients such as thunderbird or outlook.
Both monitor and active modes only monitor emails sent through exim, they do not stop outgoing mail being sent through smtp clients such as thunderbird or outlook.
OSM can only monitor outgoing mail, it cannot monitor incoming mail. It is a tool for preventing spam from being sent by exim
Using OSM will not stop most spam that is generated from compromised accounts on your server however it will prevent most automated spam attacks which come from unexpected sources.
Spam that comes from compromised accounts is usually sent to a large number of recipients. OSM will not stop spam generated from compromised accounts, however it can prevent automated attacks which come from unexpected sources and reduce the amount of spam you have to deal with in your inbox.
Spam messages are often sent by hackers using “spoofed” email addresses that appear genuine but actually belong to someone else. The hacker then sends out messages containing links or attachments containing malware or viruses which infect the target’s computer and causes it problems when they open them or click on any links within them.
Use OSM with other tools such as RBL checking, greylisting and our exim-filter products for maximum effect.
Use OSM with other tools such as RBL checking, greylisting and our exim-filter products for maximum effect.
OSM can be used in combination with any other tool which checks email addresses against a blacklist or rate limit list. For example, if you have an SMTP server that supports Sender Policy Framework (SPF), you could use it as part of a SPF policy instead of just blocking all incoming messages from unknown senders.
A tool that can help ensure your mail server isn’t sending spam
OSM is a tool that can help ensure your mail server isn’t sending spam. It’s similar to the popular SpamAssassin, but it’s focused on checking outgoing messages.
