Visitor
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6 Messages
DNS / nslookup Problem
I need regular access to government websites in Trinidad and Tobago for work.
When connected through my Comcast internet service:
nslookup cso.gov.tt
times out and does not return a result.
However, when I disconnect from Comcast and use my mobile phone hotspot, the exact same command succeeds immediately.
Because the same computer works properly when connected through a different ISP, this appears to be a Comcast network, DNS, or security filtering issue rather than a problem with my device.
Could you please investigate:
- Whether Comcast has made any recent DNS, firewall, or security changes that could affect lookups involving the .gov.tt domain.
- Whether Advanced Security, SecurityEdge, xFi Security, or another Comcast filtering service may be blocking or interfering with DNS resolution for this domain.
- Whether Comcast DNS servers can successfully resolve:
cso.gov.tt - Whether there are any known issues reaching government domains in Trinidad and Tobago.
- Whether I can temporarily bypass Comcast DNS services for testing purposes.
For troubleshooting, I have already confirmed:
- The issue occurs only when using Comcast Internet.
- The same computer works correctly on a mobile hotspot.
- The failure is reproducible with:
nslookup cso.gov.tt
If necessary, I'd appreciate escalation to a Tier‑2 network or DNS support team, since this appears to be a DNS-resolution issue rather than a Wi‑Fi or browser issue.
XfinitySara
Official Employee
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2.8K Messages
2 hours ago
Hello again, @Muhomatsu! Thank you for providing such detailed technical diagnostics. You've done an excellent job isolating this down to a DNS-level response issue on our network. Here is what is likely occurring, along with the answers to your questions and how we can get this resolved:
Is Comcast blocking or filtering .gov.tt domains?
We do not intentionally block entire foreign government top-level domains. However, our automated security systems (such as xFi Advanced Security or Xfinity CyberSecure) monitor dynamic threat intelligence feeds. If an authoritative name server hosting cso.gov.tt gets flagged for an IP reputation issue or misconfigured DNSSEC records, xFi Advanced Security will drop or time out the DNS response to protect your network.
Can you temporarily bypass Comcast DNS for testing?
Yes, absolutely. You can manually assign public DNS resolvers (such as Cloudflare 1.1.1.1 / 1.0.0.1 or Google 8.8.8.8 / 8.8.4.4) directly on your computer's network adapter settings. This bypasses our default recursive DNS servers without needing to touch your gateway.
Testing & Security Features to check:
1. Open the Xfinity App.
2. Go to Account > Security > Advanced Security (or CyberSecure) and temporarily toggle it Off.
3. Try running nslookup cso.gov.tt again. If it resolves, the security layer was intercepting the traffic.
Reporting False Positives / Tier-2 Escalation:
If the domain is blocked by our automated threat security, you can report it directly to our security team for re-evaluation at spa.xfinity.com. If toggling Advanced Security Off doesn't restore resolution, please let me know. We might be able to escalate it further by having our Tier II Network Engineering teams check the lookup status on our regional recursive resolvers.
If you'd like more step-by-step guidance on updating your operating system's DNS settings or opening a security ticket, just let me know! You can also find quick walkthroughs on how to fix DNS timeouts in nslookup on Windows, online (i.e. via YouTube and other sources).
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EG
Expert
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120.1K Messages
1 hour ago
The concern is not "accessibility / disability" help related............ Topic moved here to the proper help section.
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