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This article mainly explains "how to solve the problem of slow vsftpd connection". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to solve the problem when vsftpd connection slows down.

Vsftpd is the abbreviation of "very secure FTP daemon", and security is one of its biggest features. Vsftpd is the name of a server running on a UNIX operating system. It can run on systems such as Linux, BSD, Solaris, HP-UNIX and so on. It is a completely free ftp server software with open source code.

I. problem phenomenon

According to business feedback, some hosts in the current network often encounter timeouts when they connect through ftp. After a normal response is found through manual connection, it takes a long time to connect after authentication. Check the vsftpd.conf configuration and find nothing unusual.

II. Analysis and solution

First in the local machine through the connection loop address, found that the connection is relatively fast, there is no stutter, through other hosts, connect the two addresses of the machine, found that stutter occurs. The same is true when switching to other client connections. This leads to a paradox. If there is a problem on the server side, the theoretical loopback address connection will also have a card, and if the client has a problem, it will also be the case for other hosts. At the same time, ping returns packets very quickly, and when you connect directly, the interface for entering the user name is also very fast. Let my colleagues on the network grab a bag and take a look:

By looking at the package information, it is found that the delay in the authentication process is about 20s. Where is the 20s spent?

After querying the problem of slow vsftpd connection on the Internet, it is found that there may be a big delay in the reverse_lookup_enable parameter. The man information about this number is as follows:

Reverse_lookup_enableSet to YES if you want vsftpd to transform the ip address into the hostname, before pamauthentication. This is useful if you use pam_access including the hostname. If you wantvsftpd to run on the environment where the reverse lookup for some hostname is availableand the name server doesn't respond for a while, you should set this to NO to avoid aperformance issue.Default: YES

Since the default is YES, and it attempts anti-parsing, modify it here, add reverse_lookup_enable=NO to the / etc/vsftpd/vsftpd.conf file, and restart the vsftpd service, and the problem is solved.

At this point, I believe you have a deeper understanding of "how to solve the problem of slow vsftpd connection". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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