BIND Local DNS Resolver

BIND provides a local DNS resolver for SafeSquid, reducing lookup latency and improving cache hit rates for frequently accessed domains. Why you need this: Relying on external DNS servers introduces latency, rate-limiting, and dependency on third parties. A local BIND resolver improves performance and reliability.

Prerequisites

:::note Before You Start

Linux host with root/sudo access
SafeSquid installed
Firewall allows UDP/TCP port 53 outbound (to root DNS servers or forwarders)
NTP configured (for DNSSEC validation)

:::

Installation and Configuration

1. Install BIND

Debian/Ubuntu:

sudo apt update
sudo apt install -y bind9 bind9-utils

RHEL/Rocky/CentOS:

sudo dnf install -y bind bind-utils

Verify installation:

named -v

Should print BIND version.

2. Configure BIND Options

Edit configuration file:

Debian/Ubuntu: /etc/bind/named.conf.options
RHEL/CentOS: /etc/named.conf

sudo nano /etc/bind/named.conf.options

Add/modify:

options {
  directory "/var/cache/bind";
  
  recursion yes;
  allow-recursion { 127.0.0.1; 10.0.0.0/8; 172.16.0.0/12; 192.168.0.0/16; };
  
  listen-on port 53 { 127.0.0.1; 10.0.0.1; };  // Replace 10.0.0.1 with your server IP
  allow-query { any; };
  
  dnssec-validation auto;
  auth-nxdomain no;
  minimal-responses yes;
  
  rate-limit {
    responses-per-second 25;
  };
};

Explanation:

recursion yes — Enables BIND to query upstream DNS on behalf of clients
allow-recursion — Limits recursion to private IP ranges (prevents open resolver abuse)
listen-on — IP addresses BIND listens on (127.0.0.1 + server IP)
dnssec-validation auto — Validates DNSSEC signatures
rate-limit — Prevents DNS amplification attacks

Verify configuration syntax:

sudo named-checkconf

Should return nothing (silence means success).

3. Configure Root Hints and Local Zones (Optional)

Download root hints file:

sudo curl -o /var/cache/bind/root.hints https://www.internic.net/domain/named.root

Add root hints to configuration: Edit /etc/bind/named.conf (or /etc/named.conf):

zone "." {
  type hint;
  file "/var/cache/bind/root.hints";
};

Configure local zone overrides (for internal domains): Create /etc/bind/named.conf.local:

sudo nano /etc/bind/named.conf.local

Add:

zone "corp.local" {
  type forward;
  forwarders { 10.0.0.10; 10.0.0.11; };  // Your internal DNS servers
};

Verify zone syntax:

sudo named-checkzone corp.local /dev/null

4. Enable and Start BIND

# Debian/Ubuntu:
sudo systemctl enable --now bind9
systemctl is-active bind9

# RHEL/CentOS:
sudo systemctl enable --now named
systemctl is-active named

Expected: Service shows active.

5. Point SafeSquid to Local Resolver

Edit /etc/resolv.conf on the SafeSquid server:

sudo nano /etc/resolv.conf

Set:

nameserver 127.0.0.1

Or if BIND is on a different server:

nameserver 10.0.0.1  # BIND server IP

Test DNS resolution:

dig @127.0.0.1 example.com

Expected: Answer section with IP address and low query time.

6. Harden Resolver (Production)

Enable logging: Edit /etc/bind/named.conf (or /etc/named.conf):

logging {
  channel default_log {
    file "/var/log/named/default.log" versions 5 size 10m;
    severity info;
    print-time yes;
  };
  category resolver { default_log; };
  category security { default_log; };
};

Create log directory:

sudo mkdir -p /var/log/named
sudo chown bind:bind /var/log/named

Restart BIND:

sudo systemctl restart bind9  # or named

Additional hardening:

Restrict recursion to SafeSquid server IP only (tighten allow-recursion)
Enable Response Policy Zones (RPZ) for threat blocking (optional)
Monitor logs for unusual query patterns

Verify BIND is Working

Test DNS Query

dig @127.0.0.1 example.com +stats

Expected output:

ANSWER SECTION with IP address
Query time in milliseconds
SERVER: 127.0.0.1#53 (confirming local resolver)

Check cache hit: Run the same query twice:

dig @127.0.0.1 google.com
dig @127.0.0.1 google.com

Second query should be faster (cached response).

Check BIND Status

sudo rndc status

Expected: Shows version, uptime, and statistics.

Monitor Logs

# Debian/Ubuntu:
sudo journalctl -u bind9 -f

# RHEL/CentOS:
sudo journalctl -u named -f

# Or custom log:
sudo tail -f /var/log/named/default.log

Expected log entries:

[date] info: client 192.168.1.1#port: query: example.com IN A
[date] info: resolver: success for example.com

Troubleshooting

Issue	Likely Cause	Fix
SERVFAIL on DNSSEC domains	NTP not configured or trust anchors missing	Configure NTP first, verify `dnssec-validation auto`
High query latency	No caching or blocked egress to root servers	Check firewall allows UDP/TCP 53 outbound; verify `root.hints`
”Refused” queries	Recursion restricted or listen-on mismatch	Check `allow-recursion` includes client IP; verify `listen-on` has server IP
Port 53 already in use	Another resolver (systemd-resolved, dnsmasq) running	Stop conflicting service: `sudo systemctl disable --now systemd-resolved`
Cache not working	BIND restarting frequently or low memory	Check `journalctl -u bind9` for errors; increase memory if needed

Still not working?

Test DNS path:
dig @8.8.8.8 example.com +short
If this works but local doesn’t, BIND config issue.
Check BIND configuration:
sudo named-checkconf sudo rndc status
Trace DNS query:
dig @127.0.0.1 example.com +trace
Shows full resolution path from root to answer.
Check logs:
sudo journalctl -u bind9 -n 50

Source register

Topic	Status	Source
Recursion, forwarding, `safesquid.dns.conf` stub patterns	Confirmed	This guide
DNSSEC validation dependency on NTP	Confirmed	This page, NTP

Next Steps

Monit — Monitor BIND and auto-restart if it crashes
NTP — Required for DNSSEC validation
Integrated DNS Security — Configure DNSBL for malicious domain blocking
Troubleshooting — DNS-specific troubleshooting

Related: Supporting Services Overview

Application Ecosystem

Supporting Services

Policy Management Console

Files and Folders

BIND Local DNS Resolver

BIND Local DNS Resolver

Prerequisites

Installation and Configuration

1. Install BIND

2. Configure BIND Options

3. Configure Root Hints and Local Zones (Optional)

4. Enable and Start BIND

5. Point SafeSquid to Local Resolver

6. Harden Resolver (Production)

Verify BIND is Working

Test DNS Query

Check BIND Status

Monitor Logs

Troubleshooting

Source register

Next Steps

​BIND Local DNS Resolver

​Prerequisites

​Installation and Configuration

​1. Install BIND

​2. Configure BIND Options

​3. Configure Root Hints and Local Zones (Optional)

​4. Enable and Start BIND

​5. Point SafeSquid to Local Resolver

​6. Harden Resolver (Production)

​Verify BIND is Working

​Test DNS Query

​Check BIND Status

​Monitor Logs

​Troubleshooting

​Source register

​Next Steps

BIND Local DNS Resolver

Prerequisites

Installation and Configuration

1. Install BIND

2. Configure BIND Options

3. Configure Root Hints and Local Zones (Optional)

4. Enable and Start BIND

5. Point SafeSquid to Local Resolver

6. Harden Resolver (Production)

Verify BIND is Working

Test DNS Query

Check BIND Status

Monitor Logs

Troubleshooting

Source register

Next Steps