SMTP using 3 Mobile Broadband

I'm moving so am without ADSL for a while. I'm using a Three PAYG mobile broadband connection for now but can't seem to send email via SMTP. Trying to send via any of four SMTP services I should have access to I can't connect, so assume that Three filter port 25 (don't get replies from SYN packets).

Three's web site says to use smtp-mbb.three.co.uk port 587. That server doesn't reply on port 587, but does accept email sent on port 25. Using Wireshark I can see the SMTP transaction completes correctly. However...an email I sent at 09:28 hasn't arrived come midday.

Has anyone else got a working way to send email using Three's mobile broadband service?

Gawd...my first day without a proper ISP and I already want to get back into bed and read a book!

Have you tried using the outgoing SMTP server that relates to your email account rather than the 3 one?

Indeed: "Trying to send via any of four SMTP services I should have access to I can't connect"

The emails sent via Three have now arrived so it is working, albeit slowly.

Glad to hear things are 'working'

It might be a problem/restriction with your other providers if they don't allow you to send email through their mail servers when not connected with them? You should receive an error message if they don't allow it...

NB. Your profile says Eclipse but the link you gave is for A&A ?

Ah thanks for that! Means my profile hasn't been updated in about seven years...was getting dusty and had to re-home some spiders from the corner.

What does Three gain from forcing you to use their SMTP server?

Why aren't they happy that you are relieving the load on their mail server by using someone else's server? Is this an anti-spam policy?

Is Three concerned that they will get their IP address space blacklisted by PAYG spammers who can pay just £15 in used bank notes to send 3,000,000 anonymous Viagra spams.

Does the Three SMTP server allow you to send outgoing mail with an address in the From: header that is not 'three.co.uk' ? I.e. can their SMTP server relay a mail from <johndoe@hotmail.com> or must you use <johndoe@three.co.uk> in outgoing mails?

Sounds a bit pants to me.. So if you really do need to send outgoing mail through your company's SMTP server..then you're going to have to tunnel it over secure shell or some such inconvenience..

Just another sign they don't know how to run an ISP, one of a few I came across whilst using their service. Thankfully I'm back to proper broadband so don't have to worry now!

I had a similar problem.

Just changing the outgoing port on my btinternet.com account from 25 to 587 and it worked straight away.

However my justhost account needed to use smtp-mbb.three.co.uk on port 25 for it to work.

It's a bit of a pain having 2 sets of settings - one for my home WiFi and one for Three MBB, but at leasts it now works.

lee@ljcox.com

In reply to a post by simplypeachy:

Just another sign they don't know how to run an ISP, one of a few I came across whilst using their service. Thankfully I'm back to proper broadband so don't have to worry now!

You'll find you have the same problem with any ISP. Almost every ISP blocks port 25 except to their own mail server (by default, many allow it to be unblocked on request). Almost every ISP also blocks access to their mail server from outside their network.

The answer is to use another mail provider, not tied to an ISP, and which provides access on a port other than 25. Then you only need one lot of settings no matter where you are or how you are connected.

The answer is to use another mail provider, not tied to an ISP, and which provides access on a port other than 25. Then you only need one lot of settings no matter where you are or how you are connected.

The port "other than 25" should be 587 for standard compliance. Any other port could cause issues / get you into trouble if you connect from a corporate LAN.