Proftpd上传文件一开始很快突然速度降为0

yihua2000

./configure --prefix=/usr/local/proftpd --disable-autoshadow --disable-auth-pam --disable-shadow --with-openssl-dir=/usr/local/ssl  --with-modules=mod_tls:mod_sql:mod_sql_mysql:mod_quotatab:mod_quotatab_file:mod_quotatab_sql:mod_wrap:mod_ratio:mod_rewrite --with-includes=/usr/local/ssl/include/openssl:/usr/local/mysql/include/mysql --with-libraries=/usr/local/lib:/usr/local/ssl:/usr/local/mysql/lib/mysql --enable-tunable-buffer-size --enable-sendfile，这是我的配置在内网速度很快几乎不断，外网上传文件时初速达100K，中途会突然变为0KB,过好长时间又会继续传然后再降速~~~~是否和配置有关呢？