When serving traffic across continents, latency becomes critical. For our USA/UK user base, we need sub-100ms responses. Standard DNS won't cut it - we require intelligent routing that considers:

• Real-time network conditions
• Server health monitoring
• ASN-based routing (not just geographic coordinates)

For mission-critical applications:

// Sample API call for NS1 GeoDNS
const ns1 = require('ns1-api');
ns1.zone('example.com')
   .record('www', 'CNAME')
   .addFilter('geotarget_country', 'US,GB')
   .addFilter('select_first_n', 1);

Key players:

For startups:

# Terraform config for AWS Route53 Latency Routing
resource "aws_route53_record" "geo" {
  zone_id = aws_route53_zone.primary.zone_id
  name    = "www.example.com"
  type    = "CNAME"
  set_identifier = "us-east"
  
  latency_routing_policy {
    region = "us-east-1"
  }
  records = ["us-east-lb.example.com"]
}

Other budget options:

• DNS Made Easy: $30/mo minimum
• Constellix: 14-day free trial

Watch for these issues:

1. TTL mismatches causing cache poisoning
2. Mobile carrier proxies (especially in UK)
3. IPv6 vs IPv4 routing differences

Debugging tip:

dig +nord @8.8.8.8 www.example.com
;; CLIENT-SUBNET: 81.2.69.142/24/UK

When serving website traffic across continents, traditional DNS resolution creates suboptimal routing. Consider this typical scenario:

// Problematic DNS behavior example
const userLocation = detectUserGeo(); // Returns 'UK' or 'USA'
const serverIP = resolveDNS('example.com'); // Always returns US server IP

The latency impact becomes measurable when analyzing traceroute data. UK users connecting to US servers often experience 100+ ms additional latency compared to local servers.

After testing multiple providers, these solutions deliver reliable geographic routing:

• Amazon Route 53: Latency-based routing with continuous health checks
• Cloudflare DNS: Anycast network with edge locations in 250+ cities
• NS1

resource "aws_route53_record" "www" {
  zone_id = aws_route53_zone.primary.zone_id
  name    = "www.example.com"
  type    = "A"

  latency_routing_policy {
    region = "us-east-1"
  }

  set_identifier = "US-East"
  records        = ["192.0.2.44"]
}

resource "aws_route53_record" "www_uk" {
  zone_id = aws_route53_zone.primary.zone_id
  name    = "www.example.com"
  type    = "A"

  latency_routing_policy {
    region = "eu-west-2"
  }

  set_identifier = "UK-London"
  records        = ["198.51.100.12"]
}

// Node.js middleware for fallback routing
app.use((req, res, next) => {
  const optimalDC = geoip.lookup(req.ip).country === 'GB' 
    ? 'uk-backend' 
    : 'us-backend';
  
  req.serverPool = loadBalancers[optimalDC];
  next();
});