On Wed 21 Mar 2018 at 20:02:55 (+0000), Brian wrote: > On Tue 20 Mar 2018 at 17:07:47 -0500, David Wright wrote: > > > On Fri 23 Feb 2018 at 16:18:29 (+0000), Brian wrote: > > > > > > With > > > > > > 127.0.1.1 gmail > > > > > > in /etc/hosts the conversation would go like this: > > > > > > brian@desktop:~$ telnet bendel.debian.org 25 > > > Trying 82.195.75.100... > > > Connected to bendel.debian.org. > > > Escape character is '^]'. > > > 220 bendel.debian.org ESMTP Postfix > > > helo gmail > > > 250 bendel.debian.org > > > mail from:<some...@debian.org> > > > 250 2.1.0 Ok > > > rcpt to:<debian-user@lists.debian.org> > > > 504 5.5.2 <gmail>: Helo command rejected: need fully-qualified hostname > > > > > > gmail.com is ok with bendel. > > > > > > OTOH: > > > > > > brian@desktop:~$ telnet cloud11.unlimitedwebhosting.co.uk 25 > > > Trying 149.255.60.164... > > > Connected to cloud11.unlimitedwebhosting.co.uk. > > > Escape character is '^]'. > > > 220 cloud11.unlimitedwebhosting.co.uk ESMTP Postfix > > > helo gmail > > > 250 cloud11.unlimitedwebhosting.co.uk > > > mail from:<some...@debian.org> > > > 250 2.1.0 Ok > > > rcpt to:<deb...@lionunicorn.co.uk> > > > 250 2.1.5 Ok > > > data > > > 354 End data with <CR><LF>.<CR><LF> > > > > > > cloud11.unlimitedwebhosting.co.uk appears not to be bothered by the > > > helo; bendel is. > > > > In common with a lot of home users, I can't connect to external > > machines on port 25. I assume that's because my ISP doesn't want > > to have their IP range affected by people spamming from it. > > > > Are the dialogues above meant to show that you're at liberty to > > insert emails into those hosts because you have/could have typed > > helo gmail.com at the prompt? Is that what an open relay is? > > The two dialogues show that different mail servers treat what is > in the HELO/EHLO in two quite distinct ways. bendel cares what the > HELO/EHLO says; cloud11.unlimitedwebhosting couldn't care less. I > think both are RFC compliant. > > The behaviour of cloud11.unlimitedwebhosting does not turn it into > an open relay.
Should I assume that that's because you chose rcpt addresses that the host ought to recognise as deliverable? But like many ".home users", I submit emails for various addresses to smtp.lionunicorn.co.uk so this approach wouldn't work, would it? But to be honest, I've never engaged in a conversation like the second; the closest is the following (though I don't use this port): telnet smtp.lionunicorn.co.uk 25 Trying 149.255.58.10... Connected to smtp.lionunicorn.co.uk. Escape character is '^]'. 220 cloud11.unlimitedwebhosting.co.uk ESMTP ehlo west 250-cloud11.unlimitedwebhosting.co.uk 250-AUTH=LOGIN CRAM-MD5 PLAIN 250-AUTH LOGIN CRAM-MD5 PLAIN 250-STARTTLS 250-PIPELINING 250 8BITMIME ^] telnet> quit Connection closed. As you can see, there's now an AUTH response. [From your other post] > You don't talk to people except through an intermediary? I prefer to > know what happens to the mails I send. No, I send and receive all my emails through an always-up machine, rather than running one here. It also avoids having to open up ports for when I'm travelling. A lot of people do this, and it's likely that many of them have LANs at home whose names are best drawn from .home, .corp and .mail. Cheers, David.
