Common Troubleshooting List When Accessing The US And Hong Kong Servers Is Slow

Introduction: This article is intended for operation and maintenance and webmasters, and summarizes the "Common Troubleshooting Checklist for Slow Access to Servers in Hong Kong and the United States". The content focuses on quantifiable troubleshooting steps and priority suggestions to help quickly locate network, parsing, routing and server-side performance bottlenecks, and improve recovery efficiency and user experience.

Preliminary network detection and delay measurement

First, perform basic connectivity and delay measurements: use ping, traceroute or mtr to compare the round-trip delay and packet loss rate, and record the results in different time periods. Compare the difference in RTT from domestic and overseas nodes to the US/Hong Kong server to identify whether the access is slow due to link jitter, packet loss or single-hop delay.

DNS resolution and domain name configuration troubleshooting

Slow DNS resolution will significantly affect the first access time. Check authoritative name resolver response times, TTL settings, and whether there are incorrect CNAME chains. It is recommended to test and compare the public resolution (such as 8.8.8.8) with the operator's resolution to confirm whether there is DNS pollution or resolution path problems, and optimize the DNS caching strategy and GeoDNS configuration.

Diagnosis of routing and operator link problems

Routing selection and operator peering directly affect access speed. Use BGP path query and ISP Looking Glass to check whether the route is detoured or has abnormal AS paths. If there is cross-border link congestion or poor-quality transit, you should communicate with your ISP or consider replacing transit nodes and enabling multi-link redundancy.

Bandwidth utilization and network congestion analysis

Check whether there is a delay caused by link bandwidth saturation or sudden traffic increase. View port traffic, number of connections, and burst traffic statistics, and analyze whether bandwidth is occupied by large-traffic tasks (backup, synchronization, DDoS). Enable traffic control, QoS or offloading strategies when necessary to avoid congestion during peak hours.

Server-side performance and application layer bottlenecks

If the network is normal, check the server side: CPU, memory, disk IO and database slow queries will all extend the response time. Analyze the number of web server connections, thread pools, keep-alives and cache hit rates, view application logs and slow query logs, and optimize code, indexing and caching strategies to shorten response delays.

Security device and middleware configuration check

Improper configuration of firewalls, IPS/IDS, anti-DDoS, proxies, or CDN can introduce additional delays. Check whether there are false interceptions, large number of retransmissions or MTU inconsistencies. Test the difference between returning to the source directly and through middleware, locate whether there is a processing bottleneck in the middle device, and adjust policies or rules.

Summary and suggestions

It is recommended to execute the above list according to the "Measure→Locate→Repair→Verify" process, giving priority to solving the problems of high packet loss and routing detours, and then dealing with DNS and server performance. Establishing continuous monitoring and alerting, deploying in multiple regions or using CDN/dedicated lines can alleviate short-term problems with cross-border access. If further diagnosis is needed, save the logs and packet capture results to facilitate communication with the ISP or cloud vendor.