🟡 Medium   ⏱ 5–30 min  Last verified: 19 May 2026
Affected versions: SUSE Linux Enterprise Server 16

📖 ~1 min read

Table of contents
  1. Symptom & Impact
  2. Environment & Reproduction
  3. Root Cause Analysis
  4. Quick Triage
  5. Step-by-Step Diagnosis
  6. Solution – Primary Fix
  7. Solution – Alternative Approaches
  8. Verification & Acceptance Criteria
  9. Rollback Plan
  10. Prevention & Hardening
  11. Related Errors & Cross-Refs
  12. References & Further Reading

Symptom & Impact

SSH and console logins succeed but pause for ~30 seconds before returning a shell.

Environment & Reproduction

Seen on SLES 16 hosts joined to Active Directory with multiple unreachable DCs.

Root Cause Analysis

SSSD walks the DC list with default timeouts before falling back to a reachable controller.

Quick Triage

Run `getent passwd ` and `time id ` to measure baseline lookup.

Step-by-Step Diagnosis

Tail `/var/log/sssd/sssd_.log` while reproducing to see DC timeouts.

Illustrative mockup for sles-16 — sssd_auth-slow_terminal
Terminal diagnostics for SSSD authentication takes 30+ seconds against AD — Illustrative mockup — Progressive Robot

Solution – Primary Fix

Tune `dns_resolver_timeout` and `ldap_network_timeout` in `/etc/sssd/sssd.conf`.

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Illustrative mockup for sles-16 — sssd_auth-slow_logs
Logs and evidence for SSSD authentication takes 30+ seconds against AD — Illustrative mockup — Progressive Robot

Solution – Alternative Approaches

Configure `ad_site` to bind the host to its nearest AD site.

Verification & Acceptance Criteria

`time id ` returns in under 2 seconds and login is immediate.

Rollback Plan

Restore `/etc/sssd/sssd.conf` from snapper if tuning breaks lookups.

Prevention & Hardening

Monitor DC reachability and prune stale entries from `_msdcs` DNS zones.

Often coincides with Kerberos `KRB5_KDC_UNREACH` warnings.

Related tutorial: View the step-by-step tutorial for sles-16.

View all sles-16 tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

SUSE SSSD and AD integration documentation.

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