Red Hat Bugzilla – Bug 42970
wu-ftpd has long delay while connecting
Last modified: 2007-04-18 12:33:29 EDT
Description of Problem: wu-ftpd performs a reverse DNS lookup for incoming connections and this option can't be defeated
How Reproducible: Every time.
Steps to Reproduce:
1. install wu-ftpd 2.6-1-16 from RPM on RH71 CD1.
2. connect to the wu-ftpd server from a machine that's not resolvable in the reverse DNS.
3. experience delay of 30 seconds between client connecting to wu-ftpd server and username prompt.
Actual Results: 30 second delay before allowed to enter username.
Expected Results: Near instantaneous response with username prompt.
Additional Information: wu-ftpd can't be told to not perform a reverse DNS lookup. The "-I" option doesn't help (switching off ident). The version in this RPM seems to have been compiled with a switch requiring reverse DNS. Having the connecting host in the /etc/hosts file doesn't help. Disabling DNS for the server running wu-ftpd by renaming/removing the /etc/resolv.conf file is the only workaround I've found, but this totally disables DNS lookups for the server.
This behavior is intentional - most people want to log hostnames rather
than/in addition to IP addresses.
The right fix is to fix up the DNS responsible for the client's IP.
If you need to work around buggy DNS servers, you have to recompile with
The right fix for this is to have a option to turn it off, rather than to assume that everyone using it has access to the DNS server from which the connections will be made. Yeah, I could fix the world's DNS problems, but my schedule is already pretty packed. Way too many times the reverse DNS entries are poorly maintained, often missing, especially by those administering Windoze boxes.
Oddly enough, this seems to be the only entry about this in bugzilla. There are dozens of Internet references and deja entries with others upset about this.
Another troubling aspect of wu-ftpd is the wide variances from one revision to the next of /etc/ftp* entries, command line switches under which the package is compiled, etc. We need some stability here.
I have the same issue, but the delay is more than 30s ( around
2min).Our server is behind a firewall that drop connection after sync
timeout. Is it possible to turn off the reverse lookup option without
Will be any release that implement this change.
PS: I have the same issue with telnet.