block outgoing icmp linux mail forwarding

by jamied_uk 15th January 2012, 18:14

http://linuxpoison.blogspot.com/2010/01/how-to-disable-icmp-redirects-in-linux.html

this is to stop spam coming from linux box

Instruction from above site:

Disable ICMP Redirects:
In most of the Linux flavors (Debian, Ubuntu, Redhat Enterprise linux, OpenSuSe) ICMP Redirects can be dynamically disabled on the host by adding the proper entries in the /etc/sysctl.conf configuration file. Simply edit the /etc/sysctl.conf file and add the following entries:

For IPv4

net.ipv4.conf.all.accept_redirects = 1
net.ipv4.conf.all.send_redirects = 1

For Ipv6

net.ipv6.conf.all.accept_redirects = 1
net.ipv6.conf.all.send_redirects = 1

Read more: http://linuxpoison.blogspot.co.uk/2010/01/how-to-disable-icmp-redirects-in-linux.html#ixzz2GUdKi600