> For the complete documentation index, see [llms.txt](https://docs.sendman.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sendman.com/other/faqs/general.md).

# General

## Does Sendman store or queue my messages?

No. Sendman forwards every message to your [SMTP backend](/admin-portal/settings/smtp-backend.md) while the client is still connected, and passes the backend's reply back to the client. A message is only accepted by Sendman once your backend has accepted it.

If your backend is unavailable or rejects a message, the client receives the corresponding error and has to retry or report it, as with a direct connection to the backend.

## Can I use Sendman with several mail servers?

Each Sendman instance delivers to exactly one [SMTP backend](/admin-portal/settings/smtp-backend.md).

## Which IP address does Sendman send from?

By default, the source address of Sendman's connections to your backend is not fixed. If your instance offers [dedicated egress gateways](/admin-portal/settings/network-connections.md#sendman-egress), you can deliver through fixed IP addresses instead.

## Can I reach Sendman on port 25 from the internet?

No. Port 25 is only available through a [network connection](/admin-portal/settings/network-connections.md). From the internet, use port 587 (STARTTLS) or 465 (SSL/TLS).

## Is IPv6 supported?

No. The [IP Allow List](/admin-portal/sendman/ip-allow-list.md), [authorization policies](/admin-portal/sendman/authorization-policies.md) and [network connections](/admin-portal/settings/network-connections.md) support IPv4 only.

## Do changes in the Admin Portal require a restart?

No. Changes to the allow list, policies, credentials and SMTP settings apply to new connections immediately. Changes to network connections are applied by the network gateway after a short time.

## Which sender addresses can my clients use?

Every sender address must be listed under **Allowed senders** in an [authorization policy](/admin-portal/sendman/authorization-policies.md) that applies to the client. In addition, your SMTP backend must accept the address. Exchange Online, for example, only accepts addresses of your accepted domains, and with SMTP AUTH only addresses the mailbox may send as.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.sendman.com/other/faqs/general.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.