There's been a lot of chatter about emailing from XPages on the blogs recently.  You might want to google around.  I believe I remember 9.0 has a new simple action for emailing.  There's also t bean or 2 about this on XSnippets on OpenNTF.org.  So if you're having problems you might want to move away from LotusScript for this.  It's never been easier.

I'm not sure I understand the question though.  "which location"?  User's have locations...  the server is the server.  I'm not an admin but if you're sending email in the typical manner then it's going out the Domino server and it's mail handling tools.  there's nothing that I know of that lets you bypass the domino server.  Meaning your XPages app, which you want to send email is not going to talk to the foreign server directly.  It will do through the domino mail router.  Now sometimes it's convenient to "cheat" a bit and by pass the initial mail router and save a mail document in mail.box directly.  then the server just delivers it and doesn't "tweak" it a bit.  But it's still using domino for the delivery.

I guess you could send a raw email direct.  I've seen people test email via telnet so should be possible.  But unless there was a Java package for that it would be an awful lot of work.

I have an application that sends email from LS that is run on the server. As David says the server does not use a location, it is just the server. I have sent mail by writing directly to mail.box and that can work, but be careful. You can can cheat the From name by doing this.

I have an xPages application which, running from a web browser, fires off a LotusScript agent.  The agent sends mail alerts to patrons based on logic garnered from Notes documents. In the past the emails mailed successfully to email addresses (which, while test addresses, were within the test domain...i.e. in the address book)

A few weeks ago we had virus problems requiring a rebuild of all the server's software (and Domino). While reinstalling Domino we installed 8.5.3 (where before I had 8.5.2 installed) , then ran the FP1 upgrade. Before rebuilding I snagged a copy of NamesNSF, (holding the server document, etc). and am using it. But now the server is not mailing out these alerts. The error I am getting when a mailsend is attempted from the LotusScript is that the "remote server is not a known TCP/IP host." .  This same server is sending out mail fine from Notes (both within the domain and outside, to the internet).  I have a hunch when sending directly from Notes it doesn't go through our server, but when sending from the LotusScript it is. But I'm not sure how the configure is botched up.

I've checked the Windows host file and it appears to be the same as the pre-rebuild one (not that I think that's the issue).

I did notice on the server log the following when it first booted up:

No messages transferred to SMTPAUTH.HOSTING.EARTHLINK.NET (host nomail.EARTHLINK.NET) via SMTP: The server is not responding.  

This server, SMTPAUTH.HOSTING.EARTHLINK.NET is the server we use to send mail directly to the internet. It is configured in the client's local address book under accounts as

Account name:    Outgoing Internet Mail
Account server name:    smtpauth.hosting.earthlink.net
Login name:    xxxxxxx
Password:    xxxxxxx
Protocol:    SMTP  
SSL:    Disabled
Only from location(s):    *
 

Any ideas?  Is there a connection document missing in the server's address book?

while I hack around a bit with Admin it is not my main area. Some of these issues can be really perplexing. Someone with solid admin experience would need to respond. It looks like it is an issue with routing from the server, but .....