DNSSEC Implementation
Issued: April 3rd, 2026
1. Overview
Contrast Security is implementing DNS Security Extensions (DNSSEC) across our service domains. This security enhancement adds cryptographic verification to our DNS records, protecting customers and the Contrast platform against DNS spoofing, cache poisoning, and man-in-the-middle attacks.
DNSSEC works by digitally signing DNS records using public-key cryptography. When a DNS resolver queries a DNSSEC-signed domain, it can verify the authenticity and integrity of the response, ensuring the DNS answer has not been tampered with in transit.
2. Implementation Schedule
The rollout is structured in two phases to minimize risk and allow monitoring between each step:
| Phase | Date | Action | Customer Impact |
| Phase 1 — Initial Signing | May 1, 2026 | DNS zone is signed with DNSSEC keys (RRSIG, DNSKEY records published) | Minimal. Signed records become available. |
| Phase 2 — Chain of Trust | May 8, 2026 | DS records submitted to TLD registry; full DNSSEC validation chain activated | Validation enforced. Most impactful step. |
| Monitoring Window | May 1–15, 2026 | Active monitoring of DNS resolution across all regions | Support team on alert. |
| Post-Implementation | May 10, 2026 | Completion notice sent to all customers | Confirmation of successful rollout. |
|
⏱ Seven-Day Gap The seven-day window between Phase 1 and Phase 2 is intentional. It allows DNS caches worldwide to refresh naturally and gives the Contrast team time to monitor for any validation issues before completing the chain of trust. |
3. Who Is Affected
SaaS Customers
For the vast majority of SaaS customers, this change should be completely transparent and require no action.
EOP / Private Cloud Customers (Enterprise On-Premises)
For the vast majority of EOP customers, this change should be completely transparent and require no action.
Customers utilizing Custom/Private DNS Resolvers (Internally Hosted DNS)
If your organization manages its own DNS infrastructure, please verify that your environment is DNSSEC-compatible. Use the checklist below to assess your readiness.
Step 1: Compatibility Checklist
Work through the following with your DNS/network team:
- Internal DNS resolvers must support DNSSEC validation (DNSSEC-aware resolvers).
- Forwarders and stub resolvers must pass through DNSSEC records (the DO bit must be set).
- Split-horizon or custom DNS zones that override Contrast Security domains must be reviewed.
- Strict DNSSEC validation policies if your resolver enforces strict validation, ensure it is configured correctly or resolution will fail with SERVFAIL.
- Firewall rules must allow DNS traffic (UDP/TCP on configured port for DNS) for DNSSEC-related record types (DNSKEY, RRSIG, DS, NSEC/NSEC3), and DNS responses larger than 512 bytes must be permitted (DNSSEC requires EDNS0 with up to 4096 byte UDP payloads). TCP DNS fallback must also be allowed.
Step 2: If Your Environment Is Not DNSSEC-Compatible
The good news: most compatibility gaps can be resolved with a DNS resolver or firewall configuration update, no infrastructure overhaul is required. The table below maps each common gap to the recommended fix:
| Issue | What To Do | Who Handles It |
|---|---|---|
| Resolver not DNSSEC-aware | Enable DNSSEC validation on your recursive resolver (BIND, Unbound, Windows DNS Server all support this natively). This is a configuration change, not an infrastructure change. | Your DNS/network team |
| Forwarder stripping DNSSEC records | Configure the forwarder to operate in transparent or pass-through mode so DNSSEC record types (RRSIG, DNSKEY, DS, NSEC/NSEC3) are passed through intact. | Your DNS/network team |
| Firewall blocking extended DNS record types | Update firewall rules to allow DNSSEC record types and ensure DNS responses larger than 512 bytes are permitted. Enable TCP DNS fallback. | Your network/security team |
| Strict DNSSEC validation causing SERVFAIL | Relax the validation policy for Contrast Security domains, or — if you have internal DNS zones that override Contrast domains — ensure those zones are DNSSEC-aware. | Your DNS/network team |
| Split-horizon DNS override | Review internal zones that resolve Contrast Security domains. Ensure those zones are DNSSEC-aware or that your resolver does not enforce strict validation on those zones. | Your DNS/network team |
4. Expected Customer Impact & Possible Symptoms
In rare cases, customers may experience brief intermittent connectivity issues during the implementation window. The table below describes the most likely symptoms and their probable causes:
| Symptom | Probable Cause | Affected Customers | Self Service Fix? |
| Intermittent connection errors to Contrast services | Stale DNS cache entries during transition | SaaS & EOP | Yes — perform a local DNS cache flush (refer to Section 5, Step 1). |
| SERVFAIL DNS responses | DNSSEC validation failure — usually resolver misconfiguration | SaaS & EOP | ⚠️ Note: Partial While Section 5 Step 3 provides diagnostic assistance, permanent resolution typically requires a DNS configuration update by your internal IT or network team. Please contact Support if the issue remains unresolved. |
| Slow or delayed DNS resolution | Recursive resolver fetching and verifying new DNSSEC records | SaaS & EOP | Yes — resolution typically occurs automatically; however, performing a local DNS cache flush can expedite the process. |
| Complete inability to resolve Contrast domains | Strict DNSSEC policy blocking unverified records | SaaS & EOP | No — resolution requires your DNS or network team to relax the validation policy or reconfigure internal zones. Please contact Contrast Support or your CSA for further assistance. |
| Contrast Agent connectivity loss | Agent uses system DNS; symptoms follow host resolver behavior | SaaS | Yes — perform a local DNS cache flush on the affected host and retry; if the issue persists, refer to the diagnostic procedures outlined in Step 3. |
⚠️ Note: Not all symptoms can be resolved through self-service
While the procedures in Section 5 effectively address cache-related issues for the majority of customers, SERVFAIL errors resulting from resolver misconfiguration or total DNS blockage due to strict DNSSEC validation policies necessitate technical intervention on your internal infrastructure; these cannot be resolved by local cache flushes.
For symptoms designated as ⚠️ Partial or ❌ No above, please contact Contrast Support or your CSA after completing initial diagnostic procedures. It is critical that any modifications to DNS resolver or firewall policies are coordinated directly with your internal IT and network security teams.
5. Customer Self-Service Troubleshooting
The procedures outlined below address the most frequent DNS-related challenges encountered throughout the implementation phase. For symptoms designated as ⚠️ Partial or ❌ No in Section 4, these instructions facilitate initial diagnosis and data collection for Support; however, permanent resolution necessitates technical intervention from your internal IT/network team in coordination with Contrast Support or your CSA.
Step 1: Flush Local DNS Cache
The most common fix for transient DNS issues during a transition is to flush the local DNS cache. Instructions by operating system:
Windows
| ipconfig /flushdns |
macOS
| sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder |
Linux (systemd-resolved)
| sudo resolvectl flush-caches |
Linux (nscd)
| sudo systemctl restart nscd |
Step 2: Verify DNS Resolution
After flushing the cache, verify that your system can resolve Contrast Security domains:
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# Test DNS resolution: nslookup [your-org].contrastsecurity.com # Check if DNSSEC records are present: dig +dnssec [your-org].contrastsecurity.com # Check for SERVFAIL (DNSSEC validation failure): dig @8.8.8.8 [your-org].contrastsecurity.com |
Step 3: Check Resolver Configuration (EOP Customers)
If issues persist, verify your DNS resolver supports DNSSEC:
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# Test if your resolver supports DNSSEC (look for 'ad' flag in response): dig @<your-resolver-ip> contrastsecurity.com +dnssec # If you see SERVFAIL, temporarily test against a public resolver: dig @8.8.8.8 [your-org].contrastsecurity.com dig @1.1.1.1 [your-org].contrastsecurity.com |
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Note for Customers If public resolvers (8.8.8.8, 1.1.1.1) return successful results but your internal resolver returns SERVFAIL, the issue lies with your internal DNS infrastructure, not with Contrast Security's implementation. |
6. Escalation Path
If issues persist after completing the self-service steps above, please contact Contrast Security Support with the following information:
- Output of: nslookup [your-org].contrastsecurity.com from the affected host
- Output of: dig +dnssec [your-org].contrastsecurity.com from the affected host
- Your geographic region and network environment (corporate VPN, on-premises, cloud-hosted)
- Whether your organization uses internal/custom DNS resolvers
- Any firewall or proxy configurations that might affect DNS traffic
| Contact Method | Details |
| Support Portal | https://support.contrastsecurity.com |
| support@contrastsecurity.com |
7. Frequently Asked Questions
Will DNSSEC affect my Contrast Agent connectivity?
The Contrast Agent uses your host system's DNS resolver. If your resolver supports DNSSEC (which most modern resolvers do), no impact is expected. Customers with custom resolvers should verify compatibility.
Will DNSSEC affect my Contrast On-Prem connectivity?
The On-Premise Contrast UI can be configured to automatically retrieve SCA library updates. This uses your host system's DNS resolver. If your resolver supports DNSSEC (which most modern resolvers do), no impact is expected. Customers with custom resolvers should verify compatibility.
Ref: Documentation on SCA Library data configuration
Ref: Support Knowledge base article on outbound connections
What is a SERVFAIL error and why would I see it?
SERVFAIL is returned by a DNS resolver when it cannot validate the DNSSEC signature chain. This typically indicates that either the resolver does not support DNSSEC validation, or there is a misconfiguration in the validation chain. Contact Contrast Support if you observe persistent SERVFAIL responses after Phase 2.
Do I need to update my firewall rules?
In most cases, no. DNSSEC records are delivered over the same UDP/TCP port 53 as standard DNS. However, ensure your firewall does not strip DNSSEC-specific record types (DNSKEY, RRSIG, DS, NSEC/NSEC3).
What happens if there is a problem during rollout?*
The Contrast team will actively monitor DNS resolution during the entire implementation window (May 1- 15). In the event of a widespread issue, we have defined rollback procedures and will communicate proactively via this bulletin and direct customer notification.
My environment uses a split-horizon DNS. What should I check?
If you have internal DNS zones that resolve Contrast Security domains differently from public DNS, ensure those zones are either DNSSEC-aware or that your internal resolvers do not enforce strict DNSSEC validation on those zones.