Dear NMGLUGers et al, Some of you may remember my consternation and annoyance over that situation I had where I could no longer receive email with any Linux desktop client, most notably Thunderbird, from Comcast imap servers; where all of the known Comcast imap servers failed for me; where I eventually discovered a workaround by using the 'canonical' server, imap.ge.xfinity.com, a server that has never provided a valid security certificate. Where only the Xfinity webmail page worked properly. At the time, all of this generated a considerable amount of interest. Some of you were exceedingly generous with your suggestions, time and effort helping me to work through it all. I'm still working to incorporate all the new understandings I gained as a result. Well guess what. I think I just discovered the proximate cause of the problem: our rented Comcast router for which we had been paying for the privilege of being abused with a for truly embarrassing period of time. Chalk it up to procrastination and matrimonial politics (aka my own stupidity.) Having had the wonderful success of finally figuring out how to set up Cloudflare DNS on Kubuntu, Ubuntu MATE, and Lubuntu machines (thank you NMGLUG, especially Anthony B), I decided I wanted to act on the notion that I should probably try to set up a Pi Hole ad-blocking firewall. But I knew that I'd first have obtain a third party router in order to obtain a configurable interface. So about a month ago I finally purchased and set up our own Netgear unit and returned the Comcast rental (even though the Netgear unit is a relatively inexpensive model, it will still take about fifteen months to recover the cost via savings from ending the Comcast rip-off; thus the decision was not completely trivial.) Other than shopping and reading quite a few questionable product reviews, the whole process was entirely simple and painless. That alone should have set me to thinking. This afternoon while updating a computer that I don't usually keep in Albuquerque or use online, I noticed that when I opened Thunderbird, email downloaded instantly. Which I did not expect because I knew Thunderbird was still configured for imap.comcast.net. Hmm. What if I set my other computer back from imap.ge.xfinity.com to imap.comcast.net? Lo and behold imap.comcast.net now works just fine. I conclude that our rented Comcast modem-router with the default crippled interface had, unknown to me and against my wishes, been configured as a firewall against the use of desktop Linux mail clients. At least that appears to be the case here in Albuquerque. Any new I-told-you-sos or similar tales of woe out there? Tom in Albuquerque