I have a great gel-ink Ricoh scanner, the Aficio SG 3100SNw that has a sort of industrial print quality to it. By that I mean that a whole lot of features you’d normally only get on an office printer, perhaps reflecting Ricoh’s business rather than consumer focus.

One feature on this multi-function device is a flat-bed scanner. This works great as a copier (and has a document feed as well!) however getting it to work as a scanner which would mail the scanned copies to me was difficult. I set up one of my small servers on a Beaglebone Black as an Exim4 server, and got the correct credentials from the Google SMTP servers and generated the one-time passwords required.

Having got email working using the SBC as a email relay (and woe if you put an open email relay on the internet – spam heaven!) then the next step was to get it working from the printer, to the SBC mail relay, to Google and thence to my normal email accounts. This required a few steps:

1. Create a new account on Google Gmail to act as the ‘sender’
2. Generate a one-time password using the Gmail features, as this email agent could not do 2-factor password authentication
3. Store that in /etc/exim4/passwd.client
4. Install Exim4 on the mail relay, and configure using dpkg
5. Avoid using SSL authentication around my home network, since managing the certificates was a layer of complexity I wished to avoid

For some 1-2 years this worked wonders and I happily scanned and transferred using email, then something broke. I suspect that it was an update in the Exim software on my receiving system as I had not updated the Ricoh firmware, but endless wandering the internet via search engines took me nowhere and it lingered for about 6 months in a broken state.

Until today, when I started stepping through moving off the Beaglebone Black onto a more capable Odroid device, and started copying the Exim configurations. At some point I took the password file across and then started the command to configure Exim:

sudo dpkg-reconfigure exim4-config

I was a bit perplexed by some of the options, but as they had worked on the other box I went there and start the reconfigure utility as well, to manually mirror the same options. Some exploration and reading of Exim’s web pages helped, but a final error on connection from the printer front panel flummoxed me. This is the very helpful admin option on the Ricoh where you need to go to the following:

• Login, using your admin PIN
• Go to Settings, System Settings, and File Transfer
• SMTP server, and press the ‘Com.Test’ function below which will test your SMTP server and port settings here.

I think the key this time was that I also read the Exim log file at /var/log/exim4/mainlog and saw that I got a weird message:

rejected EHLO from syntactically invalid argument(s): DIGITAL_MFP

Searching on this (and the message contains the server IP address and hostname, gets you eventually to a neat little blog post that has this same error and an easy fix. Further explanation is here but the basics are that an underscore is an invalid character in normal Exim HELO/EHLO messages. Once included as part of the template and dpkg-reconfigure re-run, all is well with the world!