Experience: 3–5 years

Employment Type: Full-time

Location: Sahibabad

Reports To: Engineering Manager / CTO

About the Role

We run a Zimbra Collaboration Suite (FOSS) deployment integrated with an in-house Document & Data Management System (DDMS) through single sign-on, zimlets, and a reverse-proxied service mesh. We are looking for an infrastructure specialist to own the Zimbra platform, the SSO layer (Keycloak), and the surrounding network plumbing — DNS, TLS, reverse proxy, and Docker services. You will work alongside a separate application development team: they build the zimlets and DDMS application; you make the platform they run on reliable, secure, and reproducible.

Key Responsibilities

· Administer Zimbra 10.x (FOSS): mailboxd, zmprov, zmcontrol, domain configuration, preauth keys, virtual/public service hostnames, class-of-service, and account provisioning.

· Deploy and manage zimlets delivered by the development team — zmzimletctl deployment, cache flushes, service restarts, and post-deploy health verification.

· Own the SSO layer: Keycloak realm and client administration, OIDC configuration, group and role management, LDAP user federation against Zimbra's directory, and Zimbra preauth-based seamless login.

· Manage the network path end to end: internal DNS / hosts resolution, TLS certificates and private CA trust, Caddy (or Nginx) reverse proxy configuration, CORS and Content-Security-Policy headers for cross-origin iframe embedding.

· Operate the supporting Docker Compose stack — Keycloak, PostgreSQL, MongoDB, Collabora Online — including upgrades, volumes/backups, and container networking (host-gateway,



port mappings).

· Administer Linux VMs: SSH key lifecycle and hardening, sudoers policy for delegated commands, firewall/port management, service monitoring, and log analysis (mailbox.log, proxy and container logs).

· Automate operations with Bash and PowerShell — deployment scripts, environment resets, smoke tests — and keep runbooks and integration documentation current.

· Manage mail flow and deliverability: SMTP relay configuration, DNS records (MX, SPF, DKIM, DMARC), and troubleshooting message delivery issues.

· Diagnose issues across the full chain — browser, proxy, Keycloak, Zimbra — including certificate errors, token/preauth failures, redirect loops, and WOPI callback connectivity.

Required Skills & Experience

· 3+ years in Linux system administration, with at least 2 years administering a production mail platform — Zimbra strongly preferred (Postfix/Exchange/Carbonio considered).

· Working knowledge of Zimbra internals: zmprov, zimlet deployment, preauth, LDAP directory, proxy/mailbox architecture.

· Strong networking fundamentals: TCP/IP, DNS, TLS/PKI (including private CAs), reverse proxies, NAT/firewalls.

· Hands-on Keycloak (or comparable IdP) administration and solid understanding of OIDC,



SAML, and LDAP federation.

· Docker and Docker Compose in production or lab operations.

· Confident scripting in Bash; PowerShell experience for Windows-side automation.

· SSH-based remote administration, key management, and security hardening on Ubuntu/RHEL-family servers.

· Clear documentation habits — runbooks, checklists, and reproducible environment builds.

Nice to Have

· Zimbra certification or experience with Zimbra upgrades, migrations, and backup/restore.

· Collabora Online / LibreOffice Online deployment or WOPI protocol exposure.

· Experience supporting SSO integrations for web applications (redirect flows, cookies, CSP/iframe constraints).

· Virtualization platforms (VMware, Proxmox, Hyper-V) and Windows/WSL2 environments.

· Monitoring and alerting (Zabbix, Prometheus/Grafana) for mail and proxy services.

What Success Looks Like

· The entire lab — Zimbra, Keycloak, proxy, Docker services — can be rebuilt from your documentation on a fresh machine in under a day.

· A Zimbra user reaches DDMS through SSO with zero certificate warnings and zero password prompts, and you can explain every hop in that flow.

· Zimlet and configuration rollouts are scripted, smoke-tested, and repeatable by anyone on the team.

How to Apply

Send your CV and a short note on a Zimbra (or comparable mail platform) workplace you have administered — scale, SSO setup, and one hard problem you solved — to [[email protected]].

Pay: ₹50,000.00 - ₹100,000.00 per month

Work Location: In person

📌 Zimbra & Network Infrastructure Engineer (Sahibabad)
🏢 SoOLEGAL Technologies
📍 Sahibabad