An e-mail arrives and gets challenged by Comodo AntiSpam (CAS). The sender responds to the challenge and that e-mail arrives in my mailbox. I can see the response has arrived by using the webmail interface to my account. After the response arrives, it takes 2 mail polls in the e-mail client before the e-mail shows up in my e-mail client’s Inbox.
It appears the 1st mail poll lets CAS get the response to know that the pending e-mail should be allowed. The 2nd mail poll has CAS retrieve that pending e-mail and pass it onto the e-mail client. Is this how CAS is supposed to work? If so, that means that my poll time configured in my e-mail client is not obeyed regarding challenges. Rather than getting the pending e-mail on the next mail poll after the response to the challenge has been received, it instead takes 2 mail polls to get that pending e-mail.
Why can’t CAS retrieve the challenge’s response and then also retrieve the pending e-mail within the same mail session? CAS would send LIST and TOP commands to find any challenge responses and, if some were found, then issue RETR and DEL commands within that same mail session to get the pending e-mails to pass onto the e-mail client.
If someone were to send me e-mail, and with a polling interval of 10 minutes, the minimum time to receive that pending e-mail would be 30 minutes. The first poll has CAS send the challenge. The sender gets the challenge e-mail immediately and responds immediately (to eliminate the delay at the sender’s end to respond to the challenge). The response shows up in my mailbox but it won’t be until another 10 minutes during the 2nd mail poll when CAS discovers the response in my mailbox. It won’t be until another 10 minutes in the 3rd mail poll when CAS finally delivers the pending e-mail to the e-mail client. Obviously this 3-poll requirement only occurs for non-whitelisted senders but it does mean extra delay in receiving the sender’s e-mail. In this case, I used a poll interval of 10 minutes. For some accounts, their mail poll interval is 30 minutes (so it would 1-1/2 hours before getting the e-mail from the non-whitelisted sender).
So, for non-whitelisted senders, it appears the expectation is that it will take 3 times the mail poll interval before those e-mails show up in the e-mail client. That would be the minimum delay incurred by using CAS. The delay will be much longer because sender’s often load their e-mail client, poll for new e-mails, and then unload their e-mail client until whenever they decide to next check for new e-mails.
This delay impacts first-time communications. Also, while I can whitelist some senders doesn’t mean that I want them permanently whitelisted. Not everyone that I ever communicate via e-mail will be continuing to communicate with me forever. It’s ridiculous to have an ever growing list of Allowed senders just because I happen to have one discussion with them that lasted a short time (a day or a month period). There is no option to whitelist a sender for some length of time afterwhich they get removed from the whitelist and will have to authenticate themself again. I’m surprised there is no automatic means of cleaning up the Allowed and Blocked lists and instead I have to wade through all the entries to remember who they were and decide if I want them to remain authenticated. I want these temporary senders to authenticate only once but I don’t want them authenticated forever.
So I get impacted on delivery of first-time good e-mails (i.e., sender authenticated). I also end up with an enlarging list of Allowed list of senders of which many after several months are completely worthless or irrelevant entries.