About

This is the code for my Lambdas that work a private email relay.

It's purpose is to allow email sent to my relay domains to be forwarded to my personal address, and for me to be able to reply from my personal address without my personal address ever being exposed - a reply sent to an email will appear as if it is being responded to from the address the original message was sent to.

Notes

In general this is written in a way that makes most errors result in a retry of the Lambda execution. Meaning, email that fails to send will result in a Lambda retry (the number of retries will depend on the number of retries configured for the lambda, which by default is 2.)

Setup

• DynamoDB table called emails with string partition key and index called message_id
• DynamoDB table called history with string partition key and index called id
• DynamoDB table called blocklist with string partition key and index called address
  • Entries in this table should have a format like below

    address	blocklist
    [email protected]	from_addr
    facebook.com	from_domain
    [email protected]	to_addr

• Lambda envvars
  • REGION - AWS Region e.g. eu-west-1
  • S3_BUCKET - S3 bucket to use, must exist in the defined AWS region, e.g. my-bucket-name
  • DOMAIN - email domain to service e.g. test.com
  • RECIPIENT - where to forward the email, e.g. [email protected]
  • TOKEN - some auth token, SHA-1 works well due to length, e.g. dcc96cbace4351ff561f472de34e72f37fdc115a
  • REPLY_ADDR - address to concat with token and domain as Reply-To:, e.g. replies (becomes Reply-To: <REPLY_ADDR>_<TOKEN>@<DOMAIN>)
  • NO_REPLY_ADDR - address to concat with domain, used as From: header, e.g. noreply (becomes From: <NO_REPLY_ADDR>@<DOMAIN>)
  • BOUNCE_ADDR - address to concac with domain, used as From: header in bounces e.g. bouncer (becomes From: <BOUNCE_ADDR>@<DOMAIN>)
  • FROM_ALLOWLIST - list of addresses allowed to reply, separated by ,, e.g. [email protected]
  • EXPIRY - how long to keep data in the emails table in seconds (Default: 90 days)
  • EXPIRY_HISTORY - how long to keep data in the history table in seconds (Default: 365 days)

Optional send email from scratch Lambda

This Lambda is a simple frontend that allows sending an email to an address from a masked address.

Setup

• Lambda envvars
  • AUTH_TOKEN - The web UI uses HTTP Basic Auth so this is a base64 encoded string of username:password, e.g. echo -n "test:kura | base64
  • REGION - AWS Region e.g. eu-west-1
  • DOMAIN - email domain to service e.g. test.com
• Once the Lambda is provisioned, put an API Gateway HTTP API in front of it
  • Meeds to integrate with the Lambda, using version 2.0 with a GET / route.
  • Meeds to integrate with the Lambda, using version 2.0 with a POST /send route.

Optional web Lambda

This Lambda is a simple frontend that allows viewing a history of emails received and the blocklists.

Setup

• Permission to read from the blocklist and history DynamoDB tables.
• Lambda envvars
  • AUTH_TOKEN - The web UI uses HTTP Basic Auth so this is a base64 encoded string of username:password, e.g. echo -n "test:kura | base64
• Once the Lambda is provisioned, put an API Gateway HTTP API in front of it
  • This just needs to integrate with the Lambda, using version 2.0 with a GET / route.