Pureftpd Problem Set firewall

PureftpdIt is a fast, high-quality, and fully functional ftp server. The most important thing is that it supports setting the Default Client encoding. Pureftpd is very powerful and useful,FirewallSometimes you are blocked from connecting the FTP server to the port. Let's take a look at the solution!

First, open port 21 connected to the FTP server. in addition, the connection from Port <= 20 to any location should be allowed. this is enough to cope with the "active" mode. however, this is not enough to handle all types of FTP clients. most clients use another data transmission mode called passive mode. this mode is more secure than the "active" mode, but to make it work, you have to open more ports on the firewall.

Therefore, open some ports connected to the FTP server. these ports must be greater than 1023. the number of opened ports is more than twice the maximum number of customers you expect. if you want to accept 200 concurrent sessions, it is enough to open the port 50000--50400.

Then run pure-ftp with the "-p" option, followed by the port range set on the firewall.

For example:/usr/local/sbin/pure-ftpd-p 50000: 50400 &

Different from the general concept, the more ports open for Passive FTP, the safer the FTP server, because it is less prone to data eavesdropping.

If your firewall also implements network transmission (NAT), enable the forward port (enable port forwarding for all passive ports) for all passive ports .)

On the client side, if the client is behind the firewall, the firewall must understand the FTP protocol. on the Linux Firewall (iptables), you only need to load the ip_conntrack_ftp and ip_nat_ftp modules. on OpenBSD, ISOS, And FreeBSD 5 firewall (PF), redirect all data transmitted to port 21 to the ftp Proxy.

By reading the above, I think everyone can find out where the problem is. Go and solve it! I hope this article will be useful to you!

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