Need help understanding F5 iRule

Hello

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We have some F5 LTM virtual servers using the iRule below:

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when CLIENT_ACCEPTED {

if { [IP::addr [IP::client_addr] equals "172.19.6.0/23"] } {

snat 10.19.[getfield [IP::client_addr] . 3].[getfield [IP::client_addr] . 4]

}

}

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The virtual pool member servers have three NICs and are defined on the F5 as nodes in the 172.19.24.x range. One of the NICs is in the 172.19.6.x range so I'm wondering if the iRule triggers when the virtual server receives return traffic from that NIC? I'm trying to understand what effect the rule has on the traffic and whether it is needed or just left over from legacy config. We tried adding a pool member with a 172.19.6.x IP and we saw traffic coming in but nothing outbound and zero requests processed so are trying to figure out whether it is even related to the iRule or something else entirely. Can anyone shed some light?

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Thanks

AK