Sneha Gupta

Configure Apache HTTPD with SSL/TLS from scratch — mod_ssl setup, VirtualHost HTTPS, cipher hardening, HSTS, OCSP stapling, Let's Encrypt with Certbot, SNI multi-site hosting, and mTLS client authentication. Working configs for Ubuntu/Debian and RHEL/CentOS.

Set up certificate expiry monitoring using Prometheus exporters (x509-certificate-exporter, Blackbox exporter, cert-manager metrics), PromQL alerting rules, Grafana dashboards, and AlertManager notifications for Slack and PagerDuty.

Fix the AD CS error where certificate templates aren't available for enrollment. Covers template publishing, permissions, version compatibility, and CA type issues with certutil commands.

Fix the Java SAN validation error when connecting to servers with certificates that lack Subject Alternative Names. Covers certificate regeneration with SANs, OpenSSL commands, and keytool verification.

Fix the 'RPC server is unavailable' error in Active Directory Certificate Services. Covers certificate enrollment failures, CA unreachable, auto-enrollment broken — with certutil, firewall, and DNS fixes.

Fix the 'self signed certificate in certificate chain' error in OpenSSL, Node.js, curl, Git, and npm. Covers internal CA trust, corporate proxy CAs, and proper trust store configuration.

Fix the SSH 'Host key verification failed' error. Covers removing old keys, verifying new fingerprints, StrictHostKeyChecking options, and managing known_hosts at scale — with security warnings about MITM attacks.

Fix the SSH 'Permission denied (publickey)' error. Covers wrong key file, file permissions, SSH agent, authorized_keys issues, GitHub/GitLab, AWS EC2, and sshd_config — with ssh -vvv debugging.

Fix the 'unable to get local issuer certificate' error in OpenSSL, curl, Git, npm, pip, and Docker. Covers missing CA bundles, corporate proxies, and trust store configuration for every platform.

Design hybrid PKI architecture combining on-premises AD CS with Azure services. Covers Intune certificate connector, Azure AD App Proxy for NDES, Windows Hello for Business, Intune Cloud PKI, and Azure Key Vault integration.