JMRP Blog RSS Feed Blog and portfolio of José Manuel Requena Plens, firmware and software engineer in Valencia, Spain: embedded systems, open-source tooling and self-hosting. https://jmrp.io/ en-us © 2026 José Manuel Requena Plens. Articles are licensed CC BY 4.0: https://creativecommons.org/licenses/by/4.0/ mail@jmrp.io (José Manuel Requena Plens) mail@jmrp.io (José Manuel Requena Plens) 60 Thu, 15 Oct 2026 02:43:17 GMT Astro RSS Generator (Manual) https://www.rssboard.org/rss-specification https://jmrp.io/favicon.png JMRP Blog RSS Feed https://jmrp.io/ 144 144 What building a GitLab MCP server taught me about GitLab's API https://jmrp.io/blog/013-gitlab-mcp-server-api-lessons/ https://jmrp.io/blog/013-gitlab-mcp-server-api-lessons/ Building and checking an MCP server against GitLab found a 401 that meant 403 and writes answered as successes that saved nothing; each went upstream.
Continue reading on jmrp.io →]]> Sat, 10 Oct 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) GitLabAPITestingMCP José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 GitLab fine-grained personal access tokens, one action at a time https://jmrp.io/blog/014-gitlab-fine-grained-tokens-per-action/ https://jmrp.io/blog/014-gitlab-fine-grained-tokens-per-action/ A GitLab fine-grained token holds a grant, not scopes: REST refuses outside it, GraphQL answers null. I derive what each API action needs, ahead of time.
Continue reading on jmrp.io →]]> Sat, 10 Oct 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) GitLabAPISecurityAuthentication José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 Your 4-Digit PIN Is Fine: Device-Bound Keys on ESP32-S3 https://jmrp.io/blog/012-device-bound-key-derivation/ https://jmrp.io/blog/012-device-bound-key-derivation/ Why PBKDF2 iterations can't protect a 4-digit PIN on a microcontroller, and how an eFuse-HMAC device secret plus HKDF stops offline brute force.
Continue reading on jmrp.io →]]> Mon, 22 Jun 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) SecurityCryptographyFirmwareESP32 José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 A Vault File That Fails Closed: Encrypt-then-MAC on an MCU https://jmrp.io/blog/011-encrypt-then-mac-vault/ https://jmrp.io/blog/011-encrypt-then-mac-vault/ How a hardware password manager authenticates every vault file before it decrypts: encrypt-then-MAC, verify-before-decrypt, and fail-closed reads.
Continue reading on jmrp.io →]]> Tue, 16 Jun 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) SecurityCryptographyFirmwareESP32C++ José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 What the Linker Won't Do: Packing i18n Strings on an MCU https://jmrp.io/blog/010-packed-i18n-string-pool/ https://jmrp.io/blog/010-packed-i18n-string-pool/ A build-time generator packs firmware UI translations into one string pool indexed by uint16 offsets, halving the index table on a 32-bit MCU.
Continue reading on jmrp.io →]]> Wed, 10 Jun 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) FirmwareC++EmbeddedESP32 José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 Running a Tor Bridge on Linux: obfs4 and WebTunnel Guide https://jmrp.io/blog/009-running-tor-bridge/ https://jmrp.io/blog/009-running-tor-bridge/ Guide to running obfs4 and WebTunnel Tor bridges on Linux with Nginx camouflage, firewall hardening, Prometheus monitoring, and CrowdSec.
Continue reading on jmrp.io →]]> Mon, 30 Mar 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) PrivacyLinuxSecurityNginx José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 MikroTik PPPoE + DHCPv6-PD: Dual-Stack for DIGI Spain https://jmrp.io/blog/008-mikrotik-pppoe-dualstack-digi/ https://jmrp.io/blog/008-mikrotik-pppoe-dualstack-digi/ Configure PPPoE with DHCPv6 Prefix Delegation on MikroTik RouterOS for DIGI Spain. VLAN tagging, SLAAC, prefix change handling, and firewall rules.
Continue reading on jmrp.io →]]> Sun, 15 Feb 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) MikroTikIPv6Networking José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 MikroTik WireGuard VPN: Dual-Stack IPv4/IPv6 Configuration https://jmrp.io/blog/007-mikrotik-wireguard-dual-stack-vpn/ https://jmrp.io/blog/007-mikrotik-wireguard-dual-stack-vpn/ Configure WireGuard VPN on MikroTik RouterOS with full IPv4/IPv6 dual-stack. Access your home network with native IPv6 from any connection.
Continue reading on jmrp.io →]]> Sat, 14 Feb 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) MikroTikNetworkingIPv6Security José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 MikroTik Honeypot: Trap & Auto-Block Port Scanners https://jmrp.io/blog/006-implementing-mikrotik-honeypot/ https://jmrp.io/blog/006-implementing-mikrotik-honeypot/ Configure a MikroTik honeypot to detect port scanners, log malicious activity, and auto-block attackers using firewall address lists and the RAW table.
Continue reading on jmrp.io →]]> Mon, 19 Jan 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) MikroTikSecurityNetworking José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 Implementing a Tarpit in Nginx: Trap Malicious Scanners https://jmrp.io/blog/005-implementing-tarpit-nginx/ https://jmrp.io/blog/005-implementing-tarpit-nginx/ Implement an Nginx tarpit to slow down and trap malicious bots, vulnerability scanners, and brute-force attackers. Includes CrowdSec integration.
Continue reading on jmrp.io →]]> Fri, 16 Jan 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) NginxSecurityNetworking José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 Mastering QUIC and HTTP/3 with Nginx: The Complete Guide https://jmrp.io/blog/004-enabling-quic-http3-nginx/ https://jmrp.io/blog/004-enabling-quic-http3-nginx/ Deep dive into QUIC and HTTP/3 — technical architecture, security features, and step-by-step Nginx configuration for production deployment.
Continue reading on jmrp.io →]]> Wed, 14 Jan 2026 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) NginxNetworkingSecurity José Manuel Requena Plens © 2026 José Manuel Requena Plens CC BY 4.0 Content Security Policy (CSP) with Nginx: The Complete Guide https://jmrp.io/blog/003-implementing-content-security-policy-nginx/ https://jmrp.io/blog/003-implementing-content-security-policy-nginx/ Master Content Security Policy from zero to A+ — nonces, hashes, strict-dynamic, Trusted Types, bypass prevention, and production Nginx configs.
Continue reading on jmrp.io →]]> Fri, 19 Dec 2025 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) NginxSecurityCryptography José Manuel Requena Plens © 2025 José Manuel Requena Plens CC BY 4.0 Mastering Virtual Files in Nginx: A Complete Guide https://jmrp.io/blog/002-serve-virtual-files-nginx/ https://jmrp.io/blog/002-serve-virtual-files-nginx/ Serve virtual files in Nginx without disk I/O. Covers root vs alias vs try_files, named locations, Kubernetes health endpoints, and containers.
Continue reading on jmrp.io →]]> Thu, 18 Dec 2025 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) NginxDevOpsSecurity José Manuel Requena Plens © 2025 José Manuel Requena Plens CC BY 4.0 Mastering Mutual TLS (mTLS) with Nginx: A Deep Dive https://jmrp.io/blog/001-secure-nginx-client-certificates/ https://jmrp.io/blog/001-secure-nginx-client-certificates/ Implement Mutual TLS (mTLS) with Nginx — create a CA, generate client certificates, configure CRL and OCSP revocation, and enable Zero Trust.
Continue reading on jmrp.io →]]> Tue, 16 Dec 2025 00:00:00 GMT mail@jmrp.io (José Manuel Requena Plens) NginxSecurityCryptography José Manuel Requena Plens © 2025 José Manuel Requena Plens CC BY 4.0