Problem description:

If you're using MobilChange with Exchange gateway and want to sent a SMS, you should send e-mail with recipient with SMS address type. This KB record describes, how to send fax via SMTP address type - from other mail client than MS Outlook or from internet.

Solution:

MS Exchange Internet Mail Connector has a little documented feature. When it receives SMTP address in form IMCEA<address type>-<address>@<yourcompany.com>, it converts it into valid internal address of this type. So if it receives address

IMCEASMS-0225308454@company.com

it will be converted into correct SMS address SMS:0225308454. If address should contains any of "invalid" characters (like plus or space), those characters should be written as +<hexacode>, ie.

plus = +2B
space = +20

and so on. You should "encrypt" SMS address in this way if you want to sent it through Exchange IMC.

You also should to switch gateway into SMTP-ready mode using registry item

HKEY_LOCAL_MACHINE\SOFTWARE\Datasys\MobilChange\global\system\AllowInternetSenders

You may set this item to "1" and then messages from SMTP addresses will be accepted. User with SMTP address will be added into MobilChange user database.

New registry entry: HKEY_LOCAL_MACHINE\SOFTWARE\Datasys\MobilChange\global\systemAllowIMCEAaddres. This entry sets, if mails are accepted ( 1 ) or denied ( 0 ), when they arrive in "IMCEASMS-..." format to MobilChange gateway ( are not converted by EX Internet Mail connector )

Security warning 1: If somebody send an e-mail with recipient in IMCEASMS-... form and sender in IMCEAEX-... form (with valid Exchange address), this email is converted in IMC so it look like standard "internal" e-mail. MobilChange can't find that e-mail is sent from internet - SMS will be proceed and sent! This is a security hole in MS Exchange Server. So we recommed you to disable all e-mails with any of addresses in IMCEA* form on firewall or mail relay server.

Security warning 2: The same problem may be encountered if sender has SMTP address, which is the same as SMTP address of any of your Exchange users. Recommended solution: the same as in previous point.

Tip: Disable SMS sending for MobilChange user *new*. Then internet intruders with own unique SMTP address will not be able to send any SMS - they will receive "you're not authorised to use MobilChange" e-mail instead. The same e-mail will receive administrator - and then he/she can allow using MobilChange to users which need to do so.

Tip: If you want to allow internet users to send SMS to one specific number easily, you may create Custom Recipient (Contact in Exchange 2000) and set its primary address to SMS address. Then the internet users can send faxes to custom recipient's SMTP address.

Further information:

• If recipient address is SMS (IMCEASMS-) and sender's address is SMTP (but not SMTP address of one of internal Exchange users), gateway will write security warning into Application event log. You may disable this feature in registry:

• IMCEA<address type> text is case sensitive so IMCEASMS-444@... will be converted OK but imceasms-444@.... will not.
• Handling of IMCEA* addresses in Exchange IMC is little described in MS KB record Q271575.
• This record describes MobilChange 3.1.11 and newer.

Keywords:

MobilChange

If there is something unclear, send us an email to development@datasys.cz.