A connection between the subnets behind the gateways <b>moon</b> and <b>sun</b>
is set up using the IKEv1 protocol.
With <b>ah=sha1,sha256!</b> gateway <b>moon</b> proposes the use of <b>AH</b>.
Gateway <b>sun</b> selects SHA2_256_128 for integrity protection with its
<b>ah=sha256!</b> configuration.
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Upon the successful establishment of the AH CHILD SA, client <b>alice</b> behind
gateway <b>moon</b> pings client <b>bob</b> located behind gateway <b>sun</b>.