Linux Kerberos Consulting

Secure, Centralized Authentication – MIT Kerberos & Active Directory Integration

Professional Linux Kerberos expertise for enterprise environments: from pure MIT Kerberos realms to seamless Active Directory (AD) integration using realmd/sssd, winbind, cross-realm trusts, keytab automation, GSSAPI, and hardened authentication for NFSv4, Samba, Apache, SSH, PostgreSQL, and custom applications.

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Our Linux Kerberos Services

Zwiegnet provides deep Linux Kerberos consulting to design, deploy, troubleshoot, and harden Kerberos authentication infrastructures on RHEL, AlmaLinux, Rocky Linux, Oracle Linux, Ubuntu LTS, and Debian — whether you're building a standalone MIT Kerberos environment or integrating hundreds/thousands of Linux servers into Active Directory.

Our Linux Kerberos expertise includes:

MIT Kerberos Realm Design & Deployment – KDC setup (krb5kdc/kadmind), realm hierarchy, master/slave replication, database propagation, encryption types (aes256-cts-hmac-sha1-96, aes128), and principal management.
Active Directory Integration (realmd + sssd / winbind) – Domain join automation, offline credential caching, ID mapping (idmap_ad, idmap_rid, idmap_autorid), POSIX attributes, PAM stack configuration, and group policy application via sssd-ad.
Cross-Realm Trusts & Federation – Establishing forest trusts between MIT Kerberos and AD, transitive trusts, one-way/two-way authentication, name mapping, and capath configuration.
Keytab Management & Automation – Automated keytab generation/rotation (ktutil, kadmin, msktutil), credential cache (ccache) best practices, Ansible playbooks for fleet-wide keytab deployment, and service principal creation.
GSSAPI / Kerberized Services – Kerberos-enabled NFSv4 (sec=krb5/krb5i/krb5p), Samba AD member servers, Apache mod_auth_gssapi/mod_auth_kerb, SSH GSSAPI authentication, PostgreSQL GSSAPI, Hadoop/Spark Kerberos, and custom application integration.
Security Hardening & Best Practices – Enforce strong encryption types, disable legacy (rc4, des), pre-authentication enforcement, ticket lifetime/renewal tuning, clock skew mitigation (ntp/chrony), audit logging, and protection against golden/silver ticket attacks.
Troubleshooting & Performance – Kerberos trace/debug (KRB5_TRACE, kinit -V, kvno, klist), packet capture analysis (Wireshark), slow authentication diagnosis, replication lag, and sssd cache invalidation issues.
Migration & Modernization – CentOS 7 → AlmaLinux 9 Kerberos transitions, legacy winbind → sssd migration, NIS → Kerberos/LDAP consolidation, and Solaris/HP-UX Kerberos to modern Linux migration.
Monitoring & Alerting – Nagios/Zabbix checks for KDC availability, expired tickets, replication status, keytab validity, and sssd/krb5 daemon health.

Ideal for enterprises with hybrid Windows/Linux environments, large-scale server farms, HPC clusters, secure file shares (NFSv4/krb5), SSO requirements, or regulatory compliance needs (NIST, CIS, PCI-DSS) demanding strong, centralized authentication.

Located between Madison and Milwaukee, Wisconsin since 2009 — direct access to seasoned Kerberos specialists with decades of production experience in complex AD-integrated Linux environments.

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