Japanese Vps Cn2 Deployment Practice Teaches You How To Configure Firewall And Load Balancing Optimization Experience

japanese vps cn2 usually refers to a vps that is located in a japanese computer room and uses china telecom's cn2 dedicated line or high-quality backhaul. the advantage is that it has lower latency, more stable packet loss rate and better anti-jitter for mainland chinese users. it is suitable for websites, games, agents or acceleration services for chinese users.

key points for selection include: 1) confirm whether cn2 or direct telecom backhaul is used; 2) check the measured delay and packet loss in the computer room (using ping, mtr); 3) evaluate bandwidth peak, single-core performance and io; 4) understand the provider's ddos protection strategy.

after getting on the site, first do a baseline speed test (mtr/trace in multiple places), and enable tcp optimization (such as bbr congestion control) to improve long-distance transmission efficiency.

basic deployment includes operating system updates, creating non-root users, turning off password login, configuring ssh keys, and deploying basic firewalls and intrusion detection (such as fail2ban). these measures can significantly reduce the risk of being brute-forced or successfully scanned.

1. update the system: apt/yum update & upgrade. 2. add a new user and grant sudo permissions. 3. configure ssh: use keys, disable root login, and modify the default port (if it does not affect management). 4. install fail2ban and configure common service monitoring. 5. enable and configure the firewall (see example below).

back up the ssh key and keep the emergency access method in the console; if using the cloud panel, first open the management port on the panel and then lock it on the instance.

common choices include iptables/nftables, ufw (ubuntu friendly) or firewalld (centos/rhel). the key is to allow necessary ports, limit scanning behavior, and implement connection rate limiting and whitelisting policies.

iptables example: allow ssh (change port), http/https and management ip whitelist: iptables -a input -p tcp --dport 22 -s management ip -j accept iptables -a input -p tcp --dport 22 -j drop iptables -a input -p tcp --dport 80 -j accept iptables -a input -p tcp --dport 443 -j accept and add connection speed limit: iptables -a input -p tcp --dport 22 -m connlimit --connlimit-above 3 -j reject

ufw example: ufw allow from management ip to any port 22; ufw allow 80/tcp; ufw allow 443/tcp; ufw enable

combined with fail2ban to intercept brute-force cracking logs, enable system log concentration (rsyslog) and set alarms for abnormal traffic; use cloud ddos protection and blackhole routing when necessary.

commonly used solutions include nginx as reverse proxy/load balancing, haproxy for high-concurrency tcp/http loads, and lvs for four-layer high-performance scheduling. the choice depends on application layer requirements, session persistence, and ssl termination policies.

1. nginx: configure upstream and health check, enable keepalive, worker_processes auto, enable gzip and http/2; 2. haproxy: configure backend pool, active health check, and stick-table to achieve session persistence; 3. lvs+keepalived: used in extremely high concurrency scenarios, combined with nat or dr mode to achieve high-performance forwarding.

setting up an ssl terminal in the load balancing layer can reduce back-end load; use caching (nginx proxy_cache, varnish) to reduce back-end pressure; set a reasonable timeout and maximum number of connections to avoid delays caused by queue accumulation.

the cn2 line has obvious advantages, but it still needs to be optimized at the tcp layer and application layer: enable bbr, adjust tcp parameters, set a reasonable mtu and monitor the return quality. simultaneously establish multiple lines and failover (dns/anycast/load balancing) to ensure availability.

1. enable bbr: echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf; echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf; sysctl -p. 2. tcp parameters: adjust tcp_tw_reuse, tcp_fin_timeout, tcp_keepalive, etc. to reduce time_wait and improve connection reuse. 3. mtu optimization: cooperate with mtr/trace to find the best mtu to avoid fragmentation. 4. multiple lines: configure a backup isp or overseas node to achieve automatic switching through dns low ttl or anycast.

continuously use mtr, ping, and tcping to detect packet loss and delay, combined with prometheus/grafana alarms. conduct regular failover drills to ensure that routing, dns, and load balancing configurations work seamlessly during switchovers.