title: KVM Debian - Disabling ICMP Redirect Acceptance makes SSH and ping impossible
body: <p>I am currently setting up a VPN LT2P/IPSec on my Debian KVM following this tutorial :
  <a href="http://bailey.st/blog/2011/07/06/secure-ipsecl2tp-vpn-for-on-the-road-android-devices/" rel="nofollow noreferrer">http://bailey.st/blog/2011/07/06/secure-ipsecl2tp-vpn-for-on-the-road-android-devices/</a></p>
  <p>Issuing this command :</p>
  <p><code>root@localhost:~# ipsec verify</code></p>
  <p>I got the following output</p>
  <pre><code>Checking your system to see if IPsec got installed and started correctly:
  Version check and ipsec on-path                             [OK]
  Linux Openswan U2.6.28/K2.6.32-5-686 (netkey)
  Checking for IPsec support in kernel                            [OK]
  NETKEY detected, testing for disabled ICMP send_redirects   [FAILED]
  
    Please disable /proc/sys/net/ipv4/conf/*/send_redirects
    or NETKEY will cause the sending of bogus ICMP redirects!
  
  NETKEY detected, testing for disabled ICMP accept_redirects [FAILED]
  
    Please disable /proc/sys/net/ipv4/conf/*/accept_redirects
    or NETKEY will accept bogus ICMP redirects!
  
  Checking that pluto is running                                  [OK]
  Pluto listening for IKE on udp 500                              [FAILED]
    Cannot execute command &quot;lsof -i UDP:500&quot;: No such file or directory
  Pluto listening for NAT-T on udp 4500                       [FAILED]
    Cannot execute command &quot;lsof -i UDP:4500&quot;: No such file or directory
  Checking for 'ip' command                                   [OK]
  Checking for 'iptables' command                             [OK]
  Opportunistic Encryption Support                                [DISABLED]
  </code></pre>
  <p>So I edited this setting in /etc/sysctl.conf to</p>
  <h3>Disable ICMP Redirect Acceptance</h3>
  <p><code> net.ipv4.conf.all.accept_redirects = 0</code></p>
  <p>I then restarted networking in /etc/init.d</p>
  <p>Now my problem comes : I cannot connect through SSH to my KVM anymore nor ping the ip. (The only thing I can use is VNC)</p>
  <p>How could I connect via SSH again without enabling the  ICMP Redirect Acceptance?</p>