This situation is where I would usually use Data::Dumper to help show the entire data structure:

#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
                                                                      
+                                                            
my %srciphash = (
  '10.10.10.1' => {
    '10.10.10.2' => 'gw',
    '10.10.10.3' => 'dns',
    '10.10.10.4' => 'www',
  },
  '10.10.20.1' => {
    '10.10.20.2' => 'gw',
    '10.10.20.3' => 'dns',
    '10.10.20.4' => 'www',
  },
);
                                                                      
+                                                            
foreach my $a ( keys %srciphash ){
  foreach my $b ( keys %{$srciphash{$a}} ){
    #print $b,"\t",$srciphash{$a}{$b},"\n";
  }
}
                                                                      
+                                                            
print Dumper(\%srciphash),"\n";
[download]

outputs

$VAR1 = {
          '10.10.20.1' => {
                            '10.10.20.4' => 'www',
                            '10.10.20.3' => 'dns',
                            '10.10.20.2' => 'gw'
                          },
          '10.10.10.1' => {
                            '10.10.10.2' => 'gw',
                            '10.10.10.4' => 'www',
                            '10.10.10.3' => 'dns'
                          }
        };
[download]

cp
---
"Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic."