cblomart/go-naive-mail-forward repository overview
Go Naive Mail Forward
This project aims to provide mail forwarding service. It does use a simple rules to describe the fowardings to operate.
The service contains a few simple protection mechanisms:
- Sender Policy Framework: this will check that the source of the mail is an authorized sender
- Reverse Black list: checks the presence of the sender in known black list before sending
TODO:
- allow enforcing signed message over tls
- evaluate if checking SPF on helo hostname makes sense
OVER CONTAINERS AND SPF:
Sender Policy Framework does provide a series of mechanisms to validate if a sender is authorized to send a mail.
Most often this will rely on the source ip of the connection. This source IP cannot be easily identified in containers that are often natted.
To the recieving end of the mail the source ip may also be randomised by your container platform. Especially when hosting containers in a cloud, the source IP may be difficult to identify.
In these situation to avoid being flagged as spam it is always best to use DKIM to sign message. That is why a warning is provided when relaying unsigned messages.
The service supports starttls and will warn while relaying unsigned email or in clear text
Rules
Rules are defined per block separated by ";". All blocks are evaluated to define the set of destinations addresses.
Each block is defined by multiple statements separated by ":".
The first statement defines the source address:
- can be defined as a mail address
- if empty will match all addresses of the domain
- the user part can contain the
*wildcard that will match zero or more characters - the user part can contain the
?wildcard that will match exactly one character - the user part can contain the
#wildcard that will match exactly on digit - the user part can be prefixed with
!that will negate the match done
The following statements are destination addresses:
- they are mail addresses
- the domain cannot be the same as in the source statement
- if the user part is missing the user part of the source address is used
Samples
Forward all mails for "test.it" to one user "[email protected]" :
@test.it:[email protected]
Forward all users ending with fw in the "test.it" domain to the same user (fw included) in the "hello.com" domain:
*[email protected]:@hello.com
Forward all except "admin" in the "test.it" domain to one user "[email protected]":
Tag summary
Content type
Image
Digest
Size
1.8 MB
Last updated
over 4 years ago
docker pull cblomart/go-naive-mail-forward