Unable to upload large files via ftp

Add the following lines to  lines to /etc/proftpd.conf

================
AllowRetrieveRestart on
AllowOverwrite on
AllowStoreRestart on
================

Restart ftp and this should fix the issue.

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Linux Server Security

Following are the steps for securing cpanel servers:

1. Sysctl Hardening
http://www.eth0.us/sysctl

2.Secure /tmp
http://www.eth0.us/tmp

3.LES Linux Environment Security
Linux Environment Security is intended as a facility to quickly & easily secure RedHat/RPM based environments (i.e: turbo linux, open linux). It does such by enforcing root-only permissions on system binaries (binaries that have no place being
executed by normal users), enforcing root-only path traversal on system paths, enforcing immutable bit on essential rpm package contents (i.e: coreutils), and enforcing immutable bit on shell profile scripts.

4.Removal of Insecure packages

Please check to see the packages that are not needed on a web server. You can use the command rpm -qa to list all the installed rpm packages on the server. From the list remove packages choose the packages that are not required.
Some common examples of unnecessary packages are given below.
 mtools
yp-tools
redhat-config-nfs
redhat-config-samba
tftp-server
ypserv
redhat-config-printer-gui
samba
samba-swat
cups
gmp-devel
ElectricFence
doxygen
Xfree86-xfs
redhat-config-printer
cups-libs
samba-common
samba-client

5.Firewall (CSF + LFD)
6.AIDE (Advanced Intrusion Detection Environment)
http://www.cs.tut.fi/~rammer/aide.html

7. Logwatch Installation and configuration
8. ClamAV (virus scanner) Installation with Exim on cPanel servers
9. Installing chkrootkit
10. LibSafe Installation