Good day! I've noticed an interesting interface issue with outbound mail traffic. Although the inbound SMTP-based communication works on the intended interface, on one of my dual interface systems, the outbound mail transmits on the primary and not the secondary interface. In my case, with SPF/DMARC based message validation, the outbound was not the correct public interface and would throw an error with SPF invalidating DMARC as the correct outbound is the same as my inbound interface.

Think of it this way.

eth0 - 10.0.0.1 - management
eth1 - 10.0.0.2 - synchronet / smtp / sendmail / etc.

Message traffic comes in on eth1 as does everything else. When an outbound internet message is sent, it egresses on eth0.

Anyone else see this?

The ../ctrl/sbbs.ini [Mail] section does have an Interface option, and if filled with the correct interface becomes the interface the mail service listens on. There is, though, no outbound interface configurable.

Thoughts?

Dream Master

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Re: Curious Interface Issue
By: Dream Master to All on Sat Mar 23 2019 04:43 pm

eth0 - 10.0.0.1 - management
eth1 - 10.0.0.2 - synchronet / smtp / sendmail / etc.

Message traffic comes in on eth1 as does everything else. When an outbound internet message is sent, it egresses on eth0.

Generally, your routing table is going to control this. I'm not sure I understand these interfaces, though,
as they appear to likely be on the same network. All your outbound is probably
going to head over the one
iterface.

How/what is the setup, and what is the purpose of having the separate physical interface on the same network,
rather than just IP aliasing on to eth0?

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Re: Curious Interface Issue
By: Dream Master to All on Sat Mar 23 2019 04:43 pm

The ../ctrl/sbbs.ini [Mail] section does have an Interface option, and if filled with the correct interface becomes the interface the mail service listens on. There is, though, no outbound interface configurable.

Actually, there is. It's the "OutgoingV4" option (for IPv4 outbound interface, default is 0 - for "any interface"). This option was added in the bit IPv6 commit by Deuce back in 2015 and never documented. I think I might:
1. Rename the option
2. Document it

It's supported in the [mail] and [bbs] sections of ctrl/sbbs.ini

digital man

Synchronet/BBS Terminology Definition #54:
RIP = Remote Imaging Protocol (e.g. RIPscrip)
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Re: Curious Interface Issue
By: Digital Man to Dream Master on Sun Mar 24 2019 12:08 am

Re: Curious Interface Issue
By: Dream Master to All on Sat Mar 23 2019 04:43 pm

The ../ctrl/sbbs.ini [Mail] section does have an Interface option, and if filled with the correct interface becomes the interface the mail service listens on. There is, though, no outbound interface configurable.

Actually, there is. It's the "OutgoingV4" option (for IPv4 outbound interface, default is 0 - for "any interface"). This option was added in the bit IPv6 commit by Deuce back in 2015 and never documented. I think I might: 1. Rename the option
2. Document it

It's supported in the [mail] and [bbs] sections of ctrl/sbbs.ini

I've now renamed the "OutgoingV4" sbbs.ini key to "OutboundInterface".

digital man

This Is Spinal Tap quote #16:
David St. Hubbins: I believe virtually everything I read...
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Re: Curious Interface Issue
By: Digital Man to Dream Master on Sun Mar 24 2019 12:08 am

Actually, there is. It's the "OutgoingV4" option (for IPv4 outbound interface, default is 0 - for "any interface"). This option was added in the bit IPv6 commit by Deuce back in 2015 and never documented. I think I might: 1. Rename the option
2. Document it

It's supported in the [mail] and [bbs] sections of ctrl/sbbs.ini

LOL ... documentation, something we all suck at. :) I noticed your Wiki commit, thank you.

Regarding the comment earlier about why... running a BBS on one interface, and without putting a bunch of firewall rules in place or dealing with routing, I prefer to have a management interface and a BBS interface (eth0 and eth1 respectively). I can then configure /etc/ssh/sshd_config to listen to the management interface (port 22) without interfering on inbound ssh traffic going to the BBS interface. Now, as I didn't know about the undocumented "feature", I changed sshd_config to listen on a non-well-known port allowing the entire system to run on one interface.

Ultimately, my end-game is about experiementation.

Dream Master

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LOL ... documentation, something we all suck at. :) I noticed your Wiki DM>commit, thank you.

The author of my first BBS software that I ran, Paul Meiners (GT
Power), he noted that "I write terrible documentation".

Yet, the tagline below comes to mind...

Daryl

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* OLX 1.53 * Real Sysops read the documentation; or at least skim them
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