Forum Discussion

Phung_Manh_Ha_1's avatar
Phung_Manh_Ha_1
Icon for Nimbostratus rankNimbostratus
Oct 10, 2016

Port translation for outbound with port range

I have created a wildcard VS for routing and I am trying to create an Irule which will SNAT the connection for outbound traffic with source port change to random port that unused in a specific port range, example:

when CLIENT_ACCEPTED {

if { [IP::addr [IP::client_addr] equals 10.1.1.100/32] }{

  snat 192.168.1.100 (5000 -> 5999) || I need source 10.1.1.100:X change to 192.168.1.100:5XXX

}

}

I don't know Is there any way to done this and hope your helps!

Thanks so much, Jose

application delivery
iRules
LTM

1 Reply

Sort By
  • Leonardo_Souza's avatar
    Leonardo_Souza
    Icon for Cirrocumulus rankCirrocumulus
    Oct 10, 2016

    Based in the snat command documentation, it just accepts one port: https://devcentral.f5.com/wiki/irules.snat.ashx

     

    You need to keep track of the port used, saving the information to the persistence table. For a new connection you assign the port, and save the port in the persistence table. When the connection is finished (CLIENT_CLOSED event), you need to delete the table entry. You also need to write the logic to check for next available port in the range, maybe having a global variable with an index that you increment (and return to the beginning when reach the higest number), and check that does not exit yet in the persistence table.

     

    Have a look in this link about the persistence table: https://devcentral.f5.com/articles/irules-101-12-the-session-command