Sendmail configuration data
File type: Configuration file
A cf file extension identifies a Sendmail configuration file. The cf file contains the settings and rules used by the Sendmail mail transfer agent.
Sendmail uses these files on Unix and Linux systems to control mail transfer and delivery.
Found 2 different file type records with the same cf filename suffix.
File type category:
Configuration file
Date updated: October 17, 2026
Sendmail is a mail transfer agent (MTA) that supports many kinds of mail transfer and delivery, including mail sent using the SMTP protocol. It is a descendant of the delivermail program written by Eric Allman and is well known in the free and open-source software and Unix communities. Sendmail is distributed as both free software and proprietary software.
A Sendmail cf file is a plain-text configuration file. It defines Sendmail options, mailer settings, address handling, and rules for processing and routing messages. The commonly used configuration file is named sendmail.cf.
Sendmail configuration files are used on Unix-like operating systems, including Linux. They may be written directly, but administrators commonly generate a .cf file from a higher-level .mc file with the m4 macro processor. Sendmail is still available and remains in use on some systems, although other mail transfer agents are common alternatives.
A Sendmail cf file is a plain-text file and can be opened with any text editor on Linux or another Unix-like system. A text editor is suitable for inspecting the settings and rules, but changing the file can affect mail delivery.
Sendmail reads the file as its configuration when the mail transfer agent starts or reloads its configuration. It is not normally opened as a document in a graphical application.
A Sendmail cf file does not have a useful general-purpose conversion format. It can be edited as text, but converting it to another document format would remove its function as a Sendmail configuration.
When a matching .mc source file is available, the usual alternative is to modify that file and regenerate the .cf file with the m4 macro processor. A hand-written configuration can instead be maintained directly.
Software apps that manage or store settings in cf files:
Linux/Unix
File type category:
Various data file
Date updated: November 27, 2018
The cf file extension is also related to CFwin program and used for its default project file type. CFwin is used for calculation and design of cooling rooms and refrigerators.
You can open and continue to work on these projects using CFwin.
Possibly can be exported to other formats.
Software applications that can open cf files:
Microsoft Windows
Software applications that can edit cf files:
Microsoft Windows
Software capable of saving cf files:
Microsoft Windows
Software apps that create cf files:
Microsoft Windows
Software applications that handle other tasks involving cf files:
Microsoft Windows
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