HP-UX HB v13.00 Ch-10 - Network Services
HP-UX Handbook – Rev 13.00 Page 19 (of 26)
Chapter 10 Network Services
October 29, 2013
ftp
The ftp service has historically been the file transfer service of choice. While still popular, this
service is not well suited for environments where security is a big concern. The ftp client (host)
is given only a cursory inspection of its identity (forward and reverse lookup of incoming IP
address to prevent spoofing) and it provides no privacy since everything, including, the clear
text password can be picked up with a network trace.
It is launched via the inetd process and is configured via /etc/inetd.conf
ftp stream tcp6 nowait root /usr/lbin/ftpd ftpd -l
One special characteristic of ftp is that it requires two TCP ports whose well-known service
numbers are:
ftp-data 20/tcp # File Transfer Protocol (Data)
ftp 21/tcp # File Transfer Protocol (Control)Port 20 is the control connection
Another unique feature of ftp is that it can be configured for anonymous access which means that
anyone is permitted to pick up files placed in public directories. The ftp server is configured to
constrain file system access for the anonymous user to only those public directories.
Common problems include:
Performance - Could be file system performance or the network infrastructure. It is
useful to test to eliminate file system performance issues. Check file transfer time versus
transferring a similar amount of bytes using no file systems.
The example below is sending one million full TCP segments which means the Ethernet frame
will be at capacity without performing IO operations on the ftp client or the ftp server. The
count field here should be adjusted to the size of the file being sent for testing purposes. If this
test eliminates network performance file system patches and known problems should be
examined. If the problem is network, data should be gathered via support tools such as
linkinfo and lanshow. (HP internal only download lan link tools by OS level)
# ftp <target host>
ftp> put "|dd if=/dev/zero bs=1500 count=1000000" /dev/null
200 PORT command successful.
150 Opening BINARY mode data connection for /dev/null.
1000000+0 records in
1000000+0 records out
226 Transfer complete.