DNS

Guides

Docker Operations Guides 3 pages

Docker Container Can't Connect To Internet: Fixes

Diagnose and fix outbound internet connectivity failures in Docker containers on Linux hosts. Covers DNS, iptables, bridge networking, conntrack, and firewall conflicts.

Docker container cannot connect to another container

Diagnose and fix inter-container connectivity issues in Docker, including DNS failures, network misconfiguration, and application binding problems.

Docker DNS not working inside containers

Diagnose and fix DNS resolution failures inside Docker containers, including embedded DNS issues, systemd-resolved conflicts, and network misconfiguration.

HAProxy Operations Guides 1 page

Open the HAProxy Operations Guides hub

HAProxy DNS resolver failure: stale IPs and silently misrouted traffic

Diagnose HAProxy DNS resolver failures in server-template and service-discovery deployments where stale IPs silently misroute traffic while servers report UP.

NGINX Operations Guides 2 pages

Open the NGINX Operations Guides hub

NGINX 502 Bad Gateway: Causes And How To Fix It

Diagnose and fix nginx 502 Bad Gateway errors by reading error logs, upstream variables, and connection state. Covers connection refusal, upstream crashes, oversized headers, and DNS resolution failures.

nginx: no resolver defined to resolve - dynamic upstream DNS

Fix the nginx 'no resolver defined to resolve' error when using variable-based proxy_pass, and understand dynamic upstream DNS resolution with the resolver directive and the resolve parameter.

Academy

Docker Compose Networking: Service Discovery & Ports

A guide to debugging inter-container communication, resolving port binding errors, and understanding Docker's internal DNS for seamless service discovery

BIND 9 Monitoring

Learn everything about monitoring & troubleshooting BIND 9, what metrics are important to monitor and why, and how to monitor BIND 9 with Netdata.

CoreDNS Monitoring

Learn everything about monitoring & troubleshooting CoreDNS, what metrics are important to monitor and why, and how to monitor CoreDNS with Netdata.

DNS Query Monitoring

Learn everything about monitoring & troubleshooting DNS Query, what metrics are important to monitor and why, and how to monitor DNS Query with Netdata.

DNSdist Monitoring

Learn everything about monitoring & troubleshooting DNSdist, what metrics are important to monitor and why, and how to monitor DNSdist with Netdata.

ISCBind (RNDC) Monitoring

Learn about monitoring & troubleshooting ISCBind, what metrics are important to monitor and why, and how to monitor ISCBind (RNDC) with Netdata.

NSD Monitoring

Learn everything about monitoring & troubleshooting NSD, what metrics are important to monitor and why, and how to monitor NSD with Netdata.

Pi-hole Monitoring

Learn everything about monitoring & troubleshooting Pi-hole, what metrics are important to monitor and why, and how to monitor Pi-hole with Netdata.

PowerDNS Monitoring

Learn everything about monitoring & troubleshooting PowerDNS, what metrics are important to monitor and why, and how to monitor PowerDNS with Netdata.

PowerDNS Recursor Monitoring

Learn about monitoring & troubleshooting PowerDNS Recursor, what metrics are important and why, and how to monitor PowerDNS Recursor with Netdata.

Unbound Monitoring

Learn everything about monitoring & troubleshooting Unbound, what metrics are important to monitor and why, and how to monitor Unbound with Netdata.

Resources

Best BIND DNS Monitoring Tools: 10 Ranked for 2026

Compare the 10 best BIND DNS monitoring tools for 2026: statistics-channel depth, per-second resolution, alerting quality, and cost shape, ranked.

Blog

How to monitor DNS query response time

Optimizing DNS Performance for Better Network Efficiency