Glen Huang a écrit : > I have a pptp client connection (ppp1) on a gateway. If I directly > using curl --interface ppp1 to download a file, I get full download > speed very quickly (2m/s). Why do you have to use --interface ? > But if I route my lan host to ppp1 and -o ppp1 -j MASQUERADE, running > curl to download the same file on the host starts very slow (less than > 100k/s), then the speed *slowly* increases(about 50k per second), until > it reach about 1.8m/s. While downloading the file on the host, the > gateway's cpu usage never reach 1 from the output of top. > > If I directly establish the pptp client connection on host, I quickly > get full speed again. > > I wonder what might slow down the network when the packets are > forwarded. I'm currently guess it's the masquerade target, but I'm not sure. I don't think MASQUERADE is the culprit. I would suspect first MTU issues (fragmentation, path MTU discovery). > How do I test it? Lower the MTU of the client host LAN interface below ~1460. -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
