System limitations

The following list represents the most important limitations in the InterFAX system.

Other limitations may apply but will usually not have an impact on users; however, please note that this list may change over time.

Outbound Service

  • Maximum number of pages per fax: 100 pages (more may be accommodated upon request).
  • Maximum number of email to fax recipients (total addresses in ‘To:’ and ‘Cc:’ lines.) per submission: 500 addresses.
  • Maximum number of recipients in a single submission (faxing via lists or submission via web service): 20,000 recipients.
  • Maximum total filesize of fax attachments: 20MB.
  • Maximum total filesize of fax attachments, where the email is electronically signed: 10MB.
  • Fax images are stored and visible for: 14 days.
  • For prepaid users: Fax information is kept for 30 days after the prepaid card that was used at the time has been depleted.
  • For invoiced users: Fax information is kept for 30 days after the end of the month during which the fax was sent.
  • Maximum postpone time: 14 days.
  • Unable to support password-protected files.
  • Unable to support read-only files (which bring up a pop-up when opened).
  • Macros are disabled. Do not use macros, as they may affect document output.
  • Supported attachment file types: See Supported file types for a complete list of supported file types.
  • Charset ‘Windows-31J’ is currently not supported by Windows, as a result it is not supported by InterFAX. As an alternative, please use Charset ‘shift_jis’ instead. For more information, please see the article here.
  • Maximum number of file attachments in Control Panel ‘Send Fax’: 5 attachments.
  • Maximum frequency of polling for fax status: Up to 6 requests per minute.

Inbound Service

  • An account manager may define up to 10 additional shared properties.
  • Maximum number of forwarding addresses: 25 addresses.
  • Maximum allowed time between page breaks: 600 seconds.
  • The user may download fax image/s in the following formats: PDF, TIF, PNG.
  • Users can store received messages and view them for 12 months. Extended storage period is available, please visit our pricing page for additional details.
  • Maximum frequency of polling for fax status: Up to 6 requests per minute.

SOAP Web Service

  • Maximum request size of any type: 8 MB.
  • Maximum file size when using partial upload: 20 MB.
  • Maximum frequency of polling for fax status: up to 6 requests per minute.
  • Maximum number of items returned in the following methods: (for outbound faxes) FaxStatus, FaxStatusEx, FaxQuery, FaxQuery2 and (for inbound faxes) GetList, GetList2: 100 items.
  • However, when querying by verb Parent in the FaxQuery and FaxQuery2 methods (that is, when retrieving transactions in a broadcast): 20,000 items.
  • Maximum chunk size when using GetImageChunk download (of inbound faxes): 4 MB.

REST Web Service

  • Maximum request size of any type: 8 MB.
  • Maximum frequency of polling for fax status: up to 6 requests per minute.
  • Maximum number of items returned in the following methods: (for outbound faxes) Faxes, Completed and (for inbound faxes) GetList: 25 items.
  • Requests support UTF-8 encoding only.

Online Control Panel

  • Session idle timeout (time of inactivity before user is logged out): 15 minutes.
  • Response timeout: 90 seconds.
  • Maximum file size of fax image for downloading from the site: 4 MB
  • The online control panel is supported by the following web browsers: Google Chrome, Mozilla Firefox, Microsoft Edge and Internet Explorer 11.

Password limitations for all Control Panel users

Password must be 7-16 characters long, and meet at least 3 out of 4 of the following requirements:

  • At least 1 uppercase letter (A-Z)
  • At least 1 lowercase letter (a-z)
  • At least 1 digit (0-9)
  • At least 1 special character (!@#$%&)
  • The last 4 previous passwords cannot not be re-used

To meet PCI-DSS security regulations, the following limitations are for high-authentication (PCI) users:

  • Passwords are required to be changed every 90 days.
  • Users will be temporary suspended after 3 months of control panel inactivity. Account Managers or Customer Support can reinstate these users upon request.