My wifi router was purchased one years ago, for some reason it’s not stable now, sometimes lost package when I ping it. After chat with my friends Steven, he recommended Cisco Linksys WRT54G2 which he is using, a very stable router. You can install DD-WRT firmware and leverage more new free feature, such as NFS, firewall, VPN…etc. I’m newbie, I’ll try explore more on my spare time. That’s a used router on120RMB (around $20).

I successfully installed it and turned on internet after 30 minutes, but I cannot log in my VPS by SSH on port 21, then I asked Steven’s VPS SSH to give a try, his port is 443, I cannot connect his also!! I suspected firewall on WRT54G2 maybe blocked the two ports since the router much like a Linux system, you can even run iptables command. Finally I figured out my network provider blocked port 21 and 443, how funny it is that I spend 3 hours to investigated firewall, routing table, wifi setting, NAT…etc. But forgot my sweet network provider!!

大意了，大意了！没想到21和443同时被封了，搞得我以为是路由器设定问题，弄了3个小时！最后把VPS端口号改成8080，上的飕飕的。这让我想起弟弟的iPhone没有电话信号了，他做的第一件事是拿去经销商处修理，由于过年，需要30天才能返回，其实最简单的是去先换张卡看看是不是真的手机有问题。随着经验的积累，我们遇到事情好像也更复杂的看待，其实有时候复杂的搞不定还是可以从简单入手的，尤其是系统排错方面。不知IT项目实施方面是否也如此？