Open Source Operations

I use blogger and host the files on my server, after I edit a post it has to sftp the files so they appear here. This is the process for adding them.

Adding the Blogger sftp servers to iptables.

Blogger.com lists their outbound ip’s here. (It was current Jan 19, 2009)

# always check the addresses are correct and the link above.
for i in 66.102.15.83 216.34.7.186 64.233.178.192/28  64.233.178/28
  do
             echo iptables -A INPUT -i eth0 -s $i -p tcp --dport ssh -j ACCEPT
  done

### Output
iptables -A INPUT -i eth0 -s 66.102.15.83 -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -i eth0 -s 216.34.7.186 -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -i eth0 -s 64.233.178.192/28 -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -i eth0 -s 64.233.178/28 -p tcp --dport ssh -j ACCEPT

######## Other notes
I cheated and used ipcalc to the get the subnet calculations:

  ipcalc 64.233.178.192 - 64.233.178.207

  64.233.178.192/28

written by admin

How to test if your rules are being activated:

# logging just the first packet - this shows an external host is reaching you,
# but does not flood messages with notices for every packet.

# Insert at the top of the INPUT chain a request to log only NEW connections
iptables -I INPUT -m state –state NEW -j LOG

Turning off logging on iptables:

# find the logging entry, use –line-number so you know which rule to delete.
iptables -L INPUT –line-number |egrep ‘Chain|LOG’
Chain INPUT (policy DROP)
1 LOG all — anywhere anywhere LOG level warning

# delete it
iptables –delete INPUT 1

## here’s a quicky perl script to get the same info and generate (but not execute) the delete line.

#!/usr/bin/perl

my $CHAIN_NAME;
my $RULE_NUM;

# grab the iptables output
#@iptables_output = qx{iptables -L -n --line-numbers } ;

@iptables_output = qx{~/tmp/iptables -L -n --line-numbers } ;

# cut off the newlines
chomp @iptables_output;

for my $iptables_output_line (@iptables_output) {
    ( $TMP_CHAIN_NAME ) =  $iptables_output_line =~ m/
                      \A         # at the beginning of the line
                      Chain      # match chain
                      \s+
                      (\w+(-)?\w+)
                      /xms
                          and $CHAIN_NAME = $TMP_CHAIN_NAME;

    ($RULE_NUM) = $iptables_output_line =~ m/
                                             \A # at the beginning of the line
                                             (\d)+ # match any number of numbers
                                             \s+   # some space
                                             LOG    # the literal 'LOG'
                                             /xms
                                                 and print "found a log line for $CHAIN_NAME, delete it with:\n",
                                                     "\tiptables --delete $CHAIN_NAME $RULE_NUM\n";

}

######### END perl script #######

#A couple of bash helper functions:
function iptshow () {
iptables -L $1 –line-numbers
}

iptedit () {
vi /etc/sysconfig/iptables
}

written by admin