Freeserve have a long history of prohibiting people from sending emails in different circumstances.
Years ago, one could not send an email unless the From: header was the FS account name, just that. So no chance of using FS for replying to customer emails from home!
Later, they allowed any From: header for which the MX lookup works, so
[email protected] would fail whereas
[email protected] would be OK. (even though the 2nd one is an obvious forgery) Most ISPs work like that now.
I don't know what FS do today - haven't used them for years.
They used to run a scheme whereby if one dialled in with CLI disabled, they prevented any email transmission. A crude anti-spammer measure.
Best thing is to use a 3rd party SMTP server which supports "smtp auth" authentication. One normally has to pay for those.
I have one of these at my office, and in principle anybody can set one up at home. The big problem is that most people on ADSL, even those on a fixed IP, are on an IP which was allocated from a *dynamic* IP block by their ISP. ("fixed IP" customers just get the same dynamic IP each time). And dynamic IP blocks are routinely blacklisted by ISPs everywhere! So if one runs this sort of setup, one has to config the smtp server to stuff the outgoing emails into the ISP's smtp server in turn - that one isn't likely to get blacklisted and if it does the ISP has a big incentive to sort it out.
Sorting out my own smtp server has enabled me to send emails (with the correct From: header) from anywhere, including GPRS/3G connections.
WCF
You need to ask your ISP what his smtp server name is; typically it will be like
[email protected] or
[email protected]
etc
and if they support smtp auth. And yes you need a login+pwd to get into it, otherwise any spammer could use it!
Most ISPs don't offer smtp auth, except on "business" accounts and they charge extra for those. However there are 3rd party outfits that can provide just the server.
Then you have extra config to do in Outlook or whatever, to enter this extra login+pwd.