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I have a Pi3B running an older version of Raspbian. Not going to upgrade because there's a lot of stuff I and others have written to take advantage of this particular OS version. It's in the cards at some point, but not now.

I'm using the cron MAILTO= variable to catch and send any errors that jobs generate to myself. However, the cron daemon is adding the user's name to the FROM: address. For example:

user@ address@ mydomain.com

Of course, the mail host is rejecting this primarily because it knows that's not a valid user for the mail relay. (It never gets to the "this is a bad address format" check.) This seems to be the only system service that's doing this. Of course, everything on this one is running System======D.

WTF is going on here? I've disabled cron's MAILTO parameter and just have jobs writing to a log, but I'd like to figure out why it's doing this.

I have a Pi3B running an older version of Raspbian. Not going to upgrade because there's a lot of stuff I and others have written to take advantage of this particular OS version. It's in the cards at some point, but not now. I'm using the cron MAILTO= variable to catch and send any errors that jobs generate to myself. However, the cron daemon is adding the user's name to the FROM: address. For example: user@ address@ mydomain.com Of course, the mail host is rejecting this primarily because it knows that's not a valid user for the mail relay. (It never gets to the "this is a bad address format" check.) This seems to be the only system service that's doing this. Of course, everything on this one is running System======D. WTF is going on here? I've disabled cron's MAILTO parameter and just have jobs writing to a log, but I'd like to figure out why it's doing this.
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[–] • 2 pts

Is it using postfix or mailx? You can set parameters for both to override the "from" address to make it match something that the relay accepts as well as auth if you want.

If you are using the default postfix it might be worth using mailx since you can set the config in a dot file in the home dir of the user that the cron is running as.

[–] • 1 pt

I’m using postfix as a relay for all the machines I have, and yes - I did look at ways of overwriting the sender, although postfix docs all like to claim that it is not the intent of the transfer agent to do that kind of work.

I can’t remember how I got a sendmail binary in there, since the relay and cron are on the same device.

My goal is to understand why before I start making changes that affect other machines besides this one.