BT Broadband - blocking SSL or perhaps port 25 or 587?

Hello experts,

In Oxford University we encourage home and mobile users to use our
internal smtp server (smtp.ox.ac.uk) using encrypted and authenticated
SMTP as this is a good solution for people who use all sorts of
different connections and avoids the need to keep changing smtp server
in their mail clients.

We are getting a few reports of people failing to be able to connect and
the common factor seems to be BT Broadband. It is fine with many other
ISPs including NTL and Pipex.

Does anyone know if BT are doing anything funny either with SMTP over
ssl, or ports 25 or 587 (We listen on 587 for secure smtp)? It would
explain a lot!

Thanks,

Tony

"Tony Brett" <(E-Mail Removed)> wrote in message
news:er1uj7$88b$(E-Mail Removed)...
> Hello experts,
>
> In Oxford University we encourage home and mobile users to use our
> internal smtp server (smtp.ox.ac.uk) using encrypted and authenticated
> SMTP as this is a good solution for people who use all sorts of different
> connections and avoids the need to keep changing smtp server in their mail
> clients.
>
> We are getting a few reports of people failing to be able to connect and
> the common factor seems to be BT Broadband. It is fine with many other
> ISPs including NTL and Pipex.
>
> Does anyone know if BT are doing anything funny either with SMTP over ssl,
> or ports 25 or 587 (We listen on 587 for secure smtp)? It would explain a
> lot!
>
> Thanks,
>
> Tony

The first thing you should have done was addressed your question to BT. I
doubt anyone here can speak for BT unless they work for them. You will not
find many admitting to it or they would be pestered all night and day with
questions.
You might even find all those having trouble are using the same mail
program, firewall, or other general security settings. Most ISPs do not
allow users to connect to other POP/SMTP servers anyway.

on 15/02/2007, Dev supposed :
> Most ISPs do not allow users to connect to other POP/SMTP servers anyway

Eh?

Most ISPs won't let you connect to /their/ SMTP server if you're not
using one of their connections, other than that, there should be no
issues.

(Some ISPs may also block POP3 if not on their connection)

Tony Brett wrote:

> Does anyone know if BT are doing anything funny either with SMTP over
> ssl, or ports 25 or 587 (We listen on 587 for secure smtp)? It would
> explain a lot!

I'll speculate a bit here (since I'm not on a BT connection) but even if
the ISP was filtering SMTP as an anti-zombie measure, they wouldn't
touch port 587. So if that's broken as well for your users (true
SMTP-SSL, rather than TLS over SMTP which is on port 25) then it might
not be related to filtering.

--
Jay L. T. Cornwall, http://www.esuna.co.uk/~jay/
PhD Student
Imperial College London

On Thursday 15 February 2007 9:03 pm, in MID
<45d4ca96$(E-Mail Removed)>, Dev
((E-Mail Removed)) wrote:
> "Tony Brett" <(E-Mail Removed)> wrote in message
> news:er1uj7$88b$(E-Mail Removed)...

>> Does anyone know if BT are doing anything funny either with SMTP over
>> ssl,
>> or ports 25 or 587 (We listen on 587 for secure smtp)?

Don't know about other ports, but I use a number of third party SMTP
services on port 25 from a BT connection.

> Most ISPs do not
> allow users to connect to other POP/SMTP servers anyway.

IME most ISPs don't place any restrictions on POP3, and only restrict access
to their own SMTP services so that they can only be used when using
themselves for connectivity. Some do grab port 25 traffic and route it
through their own smarthosts, but I wouldn't think they'd do that with port
587 as well.

regards,
--
Ian...

Tony Brett wrote:
> Hello experts,
>
> In Oxford University we encourage home and mobile users to use our
> internal smtp server (smtp.ox.ac.uk) using encrypted and authenticated
> SMTP as this is a good solution for people who use all sorts of
> different connections and avoids the need to keep changing smtp server
> in their mail clients.
>
> We are getting a few reports of people failing to be able to connect and
> the common factor seems to be BT Broadband. It is fine with many other
> ISPs including NTL and Pipex.
>
> Does anyone know if BT are doing anything funny either with SMTP over
> ssl, or ports 25 or 587 (We listen on 587 for secure smtp)? It would
> explain a lot!
>
> Thanks,
>
> Tony

Our main company mail server is on a BT Business Broadband 8Mbit
ADSL-enabled phone line and has been so for several years without any
major problems and about 50% of our (30) sites also have BT business
broadband (the rest are with Zen) and they are all sending and receiving
email fine, so unless you have some weird setup or someone at BT has
cocked things up I do not think it's BT.

Hopefully your router or mail server can give you some useful connection
info. If not, the BT broadband team (at least on the business side) are
generally pretty helpful once you prove you know what you're talking
about and they skip the 'reset and call us back' responses.

Dev wrote:

> The first thing you should have done was addressed your question to BT. I
> doubt anyone here can speak for BT unless they work for them. You will not
> find many admitting to it or they would be pestered all night and day with
> questions.

Yes Dev - thanks for being so useful. Not. I was after generally
opinion rather than comment. I would be as stupid as you if I had not
tried to get the information from BT first.

> You might even find all those having trouble are using the same mail
> program, firewall, or other general security settings. Most ISPs do not
> allow users to connect to other POP/SMTP servers anyway.

Do you not think we have investigated that? I told you that BT was the
common factor, NOT mail client.

Tony

Linker3000 wrote:

> Our main company mail server is on a BT Business Broadband 8Mbit
> ADSL-enabled phone line and has been so for several years without any
> major problems and about 50% of our (30) sites also have BT business
> broadband (the rest are with Zen) and they are all sending and receiving
> email fine, so unless you have some weird setup or someone at BT has
> cocked things up I do not think it's BT.

Your setup is rather different to ours then. Out main connection is via
JANET as we are a UK University! We are talking here about our
off-campus users connecting through their own broadband connections to
our smtp servers which are inside our own network.

> Hopefully your router or mail server can give you some useful connection
> info. If not, the BT broadband team (at least on the business side) are
> generally pretty helpful once you prove you know what you're talking
> about and they skip the 'reset and call us back' responses.

Thanks for the advice but we have dozens of routers and dozens of mail
servers... This is not about BT Business Broadband.

Tony

Tony Brett wrote:

> Dev wrote:
>
>> The first thing you should have done was addressed your question to
>> BT. I doubt anyone here can speak for BT unless they work for them.
>> You will not find many admitting to it or they would be pestered all
>> night and day with questions.
>
> Yes Dev - thanks for being so useful. Not. I was after generally
> opinion rather than comment. I would be as stupid as you if I had not
> tried to get the information from BT first.

Dude, way to ask for help.

Oxford University, eh? Good to see you're not getting aggressive and
overcompensating because Cambridge is leaving you behind...

If you want to know what's going on, get access to a box at the remote
location (get off your fat tech support arse and go out there, if you
have to). If you can't figure out what's going on from there (wireshark,
telnet and some of the better traceroute tools should be enough for you)
then you don't deserve your job.

Geoff

Geoff Winkless wrote:

>> Yes Dev - thanks for being so useful. Not. I was after generally
>> opinion rather than comment. I would be as stupid as you if I had not
>> tried to get the information from BT first.

> Dude, way to ask for help.

He was quite justified, Dev's response was plain rude and
unconstructive. If we were all to direct questions through the official
channels then this newsgroup need not exist.

It exists because, by and large, getting useful information out of an
ISP is like drawing blood from a stone.

--
Jay L. T. Cornwall, http://www.esuna.co.uk/~jay/
PhD Student
Imperial College London