vsftpd
Written by Kai Dietrich   
Tuesday, 02 January 2007

VSFTPD behind a dsl router

vsftpd has the possibility to set the adress it sends to connecting passive clients. Unfortunatly this address has to be a given numeric IP (up to version 2.0.3, more following). Putting in your dyndns account address just results in the following when a client connects:

Command:    PASV
Response:    500 OOPS: invalid pasv_address
Response:    500 OOPS: child died

Until up to version 2.0.3 the only solution seems to be to set up a cron job which periodically rewrites your vsftpd.conf and restarts the server.
Since version 2.0.4 there is an option to DNS-resolve the pasv_address. Taken from the changelog:

- Add pasv_addr_resolve option to allow pasv_address to get DNS resolved once at startup.


Found here :
(posted by apietrom on 07-26-2005, 02:19 PM)

#!/bin/sh
#vsftpd.conf IP update

vsftpd_conf=/etc/vsftpd/vsftpd.conf
vsftpd_log=/var/log/vsftpd.log

my_ip=`host xxxxx.dyndns.org | cut -f4 -d" "`
vsftpd_ip=`grep pasv_address $vsftpd_conf | cut -f2 -d=`

if [ "$my_ip" != "$vsftpd_ip" ] ; then
( echo ",s/$vsftpd_ip/$my_ip/g" && echo w ) | ed - $vsftpd_conf
echo `date` "$vsftpd_conf updated with $my_ip IP address" >> $vsftpd_log
/etc/init.d/vsftpd restart >> $vsftpd_log
fi


tested and it seems to work fine.
But there still is an problem - if vsftpd isn't running because you stopped it manually, the cronjob will restart it automatically. Here is a version which checks whether vsftpd is allready running and calls /etc/init.d/vsftpd restart if it is (well, I'm not good at writing shellscript):

#!/bin/sh
#vsftpd.conf IP update

vsftpd_conf=/etc/vsftpd/vsftpd.conf
vsftpd_log=/var/log/vsftpd.log

my_ip=`host xxxxx.dyndns.org | cut -f4 -d" "`
vsftpd_ip=`grep pasv_address $vsftpd_conf | cut -f2 -d=`

if [ "$my_ip" != "$vsftpd_ip" ] ; then
   #check if vsftpd is already running
   if ps -A | grep vsftpd &> /dev/null
   then
( echo ",s/$vsftpd_ip/$my_ip/g" && echo w ) | ed - $vsftpd_conf
echo `date` "$vsftpd_conf updated with $my_ip IP address" >> $vsftpd_log
/etc/init.d/vsftpd restart >> $vsftpd_log
   fi
fi

Some hints for the vsftpd.conf for setting up a low-security ftp server:

hide_ids=YES
anon_max_rate=10240
secure_email_list_enable=YES
pasv_max_port=xxx
pasv_min_port=xxx
trans_chunk_size=8192
max_per_ip=1
max_clients=1
pasv_address=xxx.xxx.xxx.xxx
Last Updated ( Tuesday, 02 January 2007 )
 
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