Netcup Looking Glass & Network Speed Test Suite

netcup is part of the leading European network operator Anexia Group, operating an enterprise-grade redundant backbone (AS197540) connected directly to Tier 1 Internet exchanges including DE-CIX Frankfurt, AMS-IX Amsterdam, and VIX Vienna. Below are official Looking Glass portals, test IPv4/IPv6 addresses, speed test files, and ping commands across all operational regions.

Germany · Nuremberg Primary Flagship Datacenter

Nuremberg Data Center

Netcup's largest core datacenter; default deployment location for all Root Servers and most VPS models. Directly peered with DE-CIX & ECIX.
IPv4: 188.68.32.1
IPv6: 2a03:4000:0:1::1
ASN: AS197540 (netcup GmbH)
EU Latency < 15ms Transatlantic ~80–100ms DE-CIX Backbone Peered
Germany · Karlsruhe ISO 27001 Redundancy Hub

Karlsruhe Data Center

Netcup's secondary German campus adjacent to Frankfurt's financial internet exchange, operating with certified green energy.
IPv4: 46.38.224.1
IPv6: 2a03:4000:2:1::1
ASN: AS197540 (netcup GmbH)
EU Latency < 15ms Frankfurt Peering Direct Dual Datacenter HA
Austria · Vienna Anexia Backbone Core

Vienna Data Center

Core datacenter owned by parent firm Anexia; central routing hub for Central & Eastern Europe directly connected to VIX exchange.
IPv4: 185.248.169.1
IPv6: 2a03:4000:60:1::1
ASN: AS197540 / AS42473 (Anexia)
Central EU < 10ms VIX Direct Peering Eastern Europe Gateway
Netherlands · Amsterdam Western Europe Transit Hub

Amsterdam Data Center

Directly peered with AMS-IX and NL-ix, one of the world's largest peering fabrics, ensuring blazing transatlantic routing.
IPv4: 31.209.112.1
Backbone: AMS-IX, NL-ix, Anexia EU Core
ASN: AS197540 (netcup GmbH)
London/Paris < 10ms AMS-IX Peered Fast CDN Origin
United States · Manassas, VA US East Coast Node

Manassas (US East) Data Center

Situated in the Ashburn data corridor in Northern Virginia, the premier hub for transatlantic trade and North American operations.
IPv4: 154.26.152.1
Backbone: Equinix Ashburn, US East Tier 1 Transit
ASN: AS197540 / Anexia US
US East Coast < 5ms US Central ~25ms Native US GeoIP
Asia Pacific · Singapore APAC Low Latency (With Quota)

Singapore Data Center

Equinix SG1 facility serving Southeast Asia and Greater China. Excellent regional ping, with fixed monthly high-speed traffic quotas.
IPv4: 154.26.155.1
⚠️ Traffic Limits: VPS 2TB/mo, RS 3TB/mo; throttles to 5–10Mbps upon overage
ASN: AS197540 / Anexia AP
Southeast Asia < 20ms Equinix SG1 Hub APAC Routing

Linux Network Tuning: Maximize Transatlantic & Cross-Border Throughput

Due to high round-trip times (RTT) across intercontinental transit lines, default Linux TCP congestion algorithms (such as Cubic) aggressively collapse their TCP congestion windows on transient packet loss. Implementing two basic sysctl optimizations unlocks full line speed on long-haul connections:

1. Enable Google BBR Congestion Control in Linux

Supported natively on Debian 11/12 and Ubuntu 20.04/22.04/24.04. Run the following command in terminal as root:

cat >> /etc/sysctl.conf << 'EOF' net.core.default_qdisc = fq net.ipv4.tcp_congestion_control = bbr EOF sysctl -p

Verify with sysctl net.ipv4.tcp_congestion_control — if the output displays bbr, throughput under high latency will improve by 3x to 5x.

2. SSH Client Keep-Alive Heartbeats (Prevent Idle Dropouts)

Stateful firewalls and NAT gateways regularly drop idle SSH connections after 2 minutes. Add keep-alive signals to your local SSH configuration (~/.ssh/config):

Host * ServerAliveInterval 30 ServerAliveCountMax 5 TCPKeepAlive yes

Datacenter Selection Verdict & Recommendations

  • Recommended for 85% of users: Nuremberg (Germany): Netcup's flagship datacenter with the deepest stock availability, fastest rollout of new hardware nodes (G12.5 Zen 5), and direct peering to major European transit exchanges. All promotional flash deals default here.
  • Disaster Recovery & High Availability: Karlsruhe (Germany): Netcup's secondary German hub, ISO 27001 certified. Pairs seamlessly with Nuremberg for active-active or active-passive European failover.
  • Central & Eastern European Operations: Vienna (Austria): Anexia backbone core node, delivering sub-15ms latency to Austria, Switzerland, the Czech Republic, and Poland.
  • Western Europe & CDN Edge Origins: Amsterdam (Netherlands): Direct interconnection with AMS-IX, ideal for multi-tenant web applications and low-latency transit across Western Europe.
  • North American Presence: Manassas, VA (US East): Located in the Ashburn datacenter alley, providing native US IP allocation and minimal latency across the Eastern Seaboard.
  • Asia-Pacific Operations: Singapore: Ultra-fast regional routing across Southeast Asia, with a fixed monthly high-speed traffic allowance (VPS 2TB / RS 3TB).