Feature Request / Improvement: Enhance Custom Nginx Configuration & Logging for Security Integrations

First and foremost, I want to commend the Nginx Proxy Manager project. It's an incredibly powerful and user-friendly tool that significantly simplifies Nginx proxy management. Its intuitive UI and robust features make it a go-to solution for many, and it truly has immense potential to be even more versatile. Thank you for your continued work on this project!

While NPM excels at simplifying proxy setup, I've encountered some significant friction points when trying to integrate advanced Nginx features and third-party security tools like CrowdSec. The current custom configuration options feel a bit too "limiting" for more complex or global requirements, leading to manual overhead and integration challenges.

Problem Description:

1. Lack of Global/Reusable Nginx Configuration Snippets (e.g., for Throttling, Security):

A major pain point is the inability to define and include reusable Nginx configuration snippets globally or across a selection of proxy hosts. For instance:

• Throttling: If I want to apply a rate-limiting limit_req or limit_conn block to multiple (or all) proxy hosts, I currently have to navigate to each host's "Advanced" tab and manually paste the same configuration snippet. This is highly inefficient and error-prone for environments with many hosts.
• Security Headers/Policies: Similarly, applying common security headers (e.g., HSTS, CSP) or other general security policies necessitates per-host manual intervention.

It would be immensely beneficial to have:
* A mechanism to define Nginx snippets (e.g., location, http, server block content) once and then apply them selectively or globally to proxy hosts.
* An include-like functionality that could reference a custom snippet for a group of hosts or all hosts, rather than relying solely on individual host configuration.

2. Challenges with Custom Log Formats for Security Tools (e.g., CrowdSec Integration):

The current logging configuration presents significant hurdles, particularly when trying to integrate with log-parsing security solutions like CrowdSec (which often act as a more advanced fail2ban).

• Fixed access_log format: NPM appears to use a predefined log_format (e.g., proxy) for access_log directives in the generated host configurations. While it's possible to define a custom log_format globally (e.g., in http_top.conf), there's no straightforward way to force all (or selected) access_log directives for proxy hosts to use this newly defined format (e.g., combined_crowdsec).
• CrowdSec Integration Impact: Security tools like CrowdSec rely on consistently formatted access logs to accurately parse fields (like client IP, HTTP status, user agent, referrer, etc.) and detect malicious patterns.
  • When the log format is not standardized or is unpredictable, it forces users to create complex and fragile custom Grok patterns for each specific log format generated by NPM.
  • As experienced in troubleshooting, even minor discrepancies or unparsed fields (like the X-Forwarded-For header, which is critical for identifying real client IPs behind a proxy, or the final proxy field in some NPM logs) can lead to parser failures, preventing effective security analysis and blocking.
  • Currently, without manual intervention on each host's advanced config to specify access_log /data/logs/proxy-host-X_access.log combined_crowdsec; (after defining combined_crowdsec globally), CrowdSec cannot reliably parse the logs using its robust, community-maintained Nginx parsers. This essentially means for every new host, I must manually adjust its logging configuration for CrowdSec to function correctly, defeating the purpose of an automated proxy manager.

Proposed Solution/Desired Outcome:

It would be highly beneficial if Nginx Proxy Manager provided:

1. A "Snippets" management section in the UI, allowing users to define reusable Nginx configuration blocks that can be easily assigned to multiple hosts (e.g., via a multi-select option on host creation/editing).
2. A global setting to choose the default access_log format for all newly created proxy hosts, or an option to override the access_log format for existing hosts in bulk. This would greatly simplify integration with log-based security tools by ensuring a consistent and well-understood log format.
3. Ensure that critical fields like X-Forwarded-For are consistently included and easily accessible/configurable within log formats for security analysis.

Implementing such features would elevate Nginx Proxy Manager's utility for users with more advanced security and configuration needs, making it an even more indispensable tool in the self-hosting and development ecosystem.

Thank you for considering these improvements!

Start with the proxy host Advanced tab and the global http_top.conf configuration mentioned in the issue, then trace how generated host configurations set access_log. Define the scope for reusable snippets and selectable log formats, and consider how existing and newly created hosts are handled; done means the requested configurations can be applied consistently without per-host manual edits.