Category Archives: networking

Linux HOWTO Enable Miltucast Ping (ICMP) Replies (Echo)

Posted on April 21, 2011 by admin

The 2.6 Linux kernel does not respond to multicast ICMP Echo requests by default. This is a setting in /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts Test it: # cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts 1 # Set it to 0 for ping replies: # echo “0” > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts # … Continue reading →

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Perl code to find an IP A in subnet B/C

Posted on June 5, 2007 by admin

my $ip = ‘1.2.3.4’; my $block1 = ‘1.2.3.0/27’; if(checkip($ip, $block1)) { print STDOUT “$ip is in $block1\n”; } else { print STDOUT “$ip is not in $block1\n”; } sub checkip() { my $ip = shift; my $block = shift; @ip1 … Continue reading →

Posted in How Tos, ip addressing, ipv4, networking, perl, Programming | Leave a comment