一直被一個問題困擾，我拿一台Linux當作某個店面的閘道器，用iptables當防火牆，其他店面也是。但這個門市都有一個問題，就是我直接ping不管是虛擬IP:192.168.xx.xx或外部IP它的response time都會從100多ms一路掉到20幾ms，然後又重複一輪，向下面這樣，但是我查過Linux的設定也沒問題跟其他店面用的都一樣，中華電信也說外部線路正常。可是這個店面上網速度頗慢，不知道哪位高手可以幫忙解釋該從哪裡檢查問題，謝謝！！
64 bytes from 192.168.12.8: icmp_seq=1 ttl=127 time=110 ms
64 bytes from 192.168.12.8: icmp_seq=2 ttl=127 time=108 ms
64 bytes from 192.168.12.8: icmp_seq=3 ttl=127 time=107 ms
...
64 bytes from 192.168.12.8: icmp_seq=39 ttl=127 time=73.5 ms
64 bytes from 192.168.12.8: icmp_seq=40 ttl=127 time=72.5 ms
64 bytes from 192.168.12.8: icmp_seq=41 ttl=127 time=70.9 ms
64 bytes from 192.168.12.8: icmp_seq=42 ttl=127 time=69.4 ms
...
64 bytes from 192.168.12.8: icmp_seq=92 ttl=127 time=32.6 ms
64 bytes from 192.168.12.8: icmp_seq=93 ttl=127 time=30.6 ms
64 bytes from 192.168.12.8: icmp_seq=94 ttl=127 time=28.9 ms
64 bytes from 192.168.12.8: icmp_seq=95 ttl=127 time=27.9 ms
64 bytes from 192.168.12.8: icmp_seq=96 ttl=127 time=26.2 ms
64 bytes from 192.168.12.8: icmp_seq=97 ttl=127 time=24.8 ms
64 bytes from 192.168.12.8: icmp_seq=98 ttl=127 time=222 ms
64 bytes from 192.168.12.8: icmp_seq=99 ttl=127 time=122 ms
...
64 bytes from 192.168.12.8: icmp_seq=107 ttl=127 time=214 ms
64 bytes from 192.168.12.8: icmp_seq=108 ttl=127 time=114 ms
64 bytes from 192.168.12.8: icmp_seq=109 ttl=127 time=115 ms
64 bytes from 192.168.12.8: icmp_seq=110 ttl=127 time=114 ms
64 bytes from 192.168.12.8: icmp_seq=111 ttl=127 time=113 ms
...