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Informations on SSL end to end on ACE module

Hello there,

I'd like to know how the ACE modules handles the traffic re-encrypted and sent to the servers in a SSL end to end scenario.

What I mean is:

the ACE terminates SSL requests for the clients and then encrypts the traffic to load balanced servers.. how is this handled?

Do the ACE initiates a one-to- one client-server encrypted connection or could it establish and

maintain a sort of ssl tunnels to the servers? (keeping the sessions low in number)

I did some research but no precise info could be found.

Any information would be apreciated.

Thanks

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Accepted Solutions
Bronze

Re: Informations on SSL end to end on ACE module

Hello Silk-

  The "TCP Server Reuse" feature is what you are describing. It is documented here:

http://www.cisco.com/en/US/docs/interfaces_modules/services_modules/ace/vA2_3_0/configuration/slb/guide/classlb.html#wpmkr1076809

One thing to understand - TCP reuse does not allow more than one client to use a   connection in the same moment of time.  A single client makes a connection on the front end, a connection is made on the   as well.  After the client sends a FIN or RST, ACE closes the connection on the front end and leaves the connection open on the  . It builds a pool of connections that it keeps open with TCP-Keepalives.

  When a new client connection comes in, ACE tries to match the connection to one in the pool.  If there is a match, ACE completes the handshake on the front end and maps it to the back end connection (the GET or whatever the request is would be send over the back end connection immediately after the 3 way handshake.)

  If the connection did not match, ACE would open a new connection on the back end.  The match is based on parameters in the SYN packet like TCP options, MSS, etc.

As this pertains to SSL, ACE would keep the back end SSL connection open (just a bit further than the 3 way handshake as referenced above of course.)

Regards,

Chris Higgins

4 REPLIES
Bronze

Re: Informations on SSL end to end on ACE module

Hello Silk,

End to End SSL is one to one.

Here is an example of how you set it up:

parameter-map type ssl PARAMMAP_SSL
  version TLS1
  rehandshake enabled

rserver host Server1
  ip address 172.16.35.1
  inservice
rserver host Server2
  ip address 172.16.35.2
  inservice
server host Server3
  ip address 172.16.35.3
  inservice

serverfarm host SSLFARM
  rserver Server1 443
    inservice
  rserver Server2 443
    inservice
  rserver Server3 443
    inservice

ssl-proxy service SSLTerm
  key key
  cert certificate
ssl-proxy service SSLInit
  ssl advanced-options PARAMMAP_SSL

class-map match-all SSLVIP
  2 match source-address 172.16.36.50 255.255.255.255 tcp eq https

policy-map type loadbalance first-match SSLPolicy
  class class-default
    serverfarm SSLFARM
    ssl-proxy client SSLInit

policy-map multi-match ALL
  class SSLVIP
    loadbalance vip inservice
    loadbalance policy SSLPolicy
    loadbalance vip icmp-reply
    ssl-proxy server SSLTerm

Regards,

Chris Higgins

New Member

Re: Informations on SSL end to end on ACE module

> End to End SSL is one to one.

...so I get no real server offloading with this scenario? Can't the ACE de/multiplex sessions?

(I don't really need configurations, just tech capability news)

EDIT: I think what I need is the TCP Reuse feature, could it  reuse SSL connections

initiated from the ACE to the servers (in the ssl end to end environment)?

Thanks

Bronze

Re: Informations on SSL end to end on ACE module

Hello Silk-

  The "TCP Server Reuse" feature is what you are describing. It is documented here:

http://www.cisco.com/en/US/docs/interfaces_modules/services_modules/ace/vA2_3_0/configuration/slb/guide/classlb.html#wpmkr1076809

One thing to understand - TCP reuse does not allow more than one client to use a   connection in the same moment of time.  A single client makes a connection on the front end, a connection is made on the   as well.  After the client sends a FIN or RST, ACE closes the connection on the front end and leaves the connection open on the  . It builds a pool of connections that it keeps open with TCP-Keepalives.

  When a new client connection comes in, ACE tries to match the connection to one in the pool.  If there is a match, ACE completes the handshake on the front end and maps it to the back end connection (the GET or whatever the request is would be send over the back end connection immediately after the 3 way handshake.)

  If the connection did not match, ACE would open a new connection on the back end.  The match is based on parameters in the SYN packet like TCP options, MSS, etc.

As this pertains to SSL, ACE would keep the back end SSL connection open (just a bit further than the 3 way handshake as referenced above of course.)

Regards,

Chris Higgins

New Member

Re: Informations on SSL end to end on ACE module

Ok, thank you very much for the insights

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