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drhawkings_2156's avatar
drhawkings_2156
Icon for Nimbostratus rankNimbostratus
May 04, 2010

inbound is DNAT and outbound is SNAT?

May I know what is the difference between theese two?

 

 

virtual kmportal_time_vs { destination 217.26.165.12:any ip protocol tcp profile fastL4 pool kmportal_pool

 

pool kmportal_pool { monitor all gateway_icmp member 192.168.3.5:any

 

 

virtual pptp_time_vs { destination 219.225.11.3:any snatpool pptp_snatpool ip protocol tcp profile fastL4 pool pptp_pool

 

pool pptp_pool { monitor all gateway_icmp member 192.168.3.34:any

 

snatpool pptp_snatpool { member 211.24.161.34

 

 

Does inbound traffic for virtual pptp_time_vs does snat?
config
design

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    May 04, 2010
    Hi,

     

     

    Snat, regardless of context of inbound/outbound will perform source address translation of the source IP address when LTM establishes the egress connection. The first VIP (kmportal_time_vs) doesn't use SNAT explicitly while the second VIP (pptp_time_vs) does use a SNAT pool. You could still have a default SNAT defined which would take effect for the first VIP.

     

     

    Does this answer your questions?

     

     

    Aaron
  • drhawkings_2156's avatar
    drhawkings_2156
    Icon for Nimbostratus rankNimbostratus
    May 05, 2010
    For virtual kmportal_time_vs, for inbound connection:when external IP(example 8.8.8.8) access 217.26.165.12, dest IP will be NAT to 192.168.3.5

     

    Therefore source IP address(8.8.8.8) remain unchange.Is that right?

     

    For outbound connection(from kmportal_pool to external 8.8.8.8) via the same session, what will be the source IP address? virtual server IP -217.26.165.12 or use the default SNAT Automap?

     

     

    For virtual pptp_time_vs,for incoming when external user(example 3.3.3.3) access 219.225.11.3, does SNAT happen for inbound or outbound only?

     

    outbound here refer to the "same session" that establish when external user access 219.225.11.3

     

    Therefore SNAT will nat source IP to 211.24.161.34?

     

  • Michael_Yates's avatar
    Michael_Yates
    Icon for Nimbostratus rankNimbostratus
    May 06, 2010
    If SNAT is applied to a Virtual Server, any traffic behind the F5 will appear to have come from the F5.

     

     

    Client IP Address - 10.10.10.10

     

    Virtual Server IP Address - 20.20.20.20

     

    Pool Server IP Address - 30.30.30.30

     

     

    If SNAT is applied to the Virtual Server then the Pool Server will see all traffic coming from 20.20.20.20. The only way that the Pool Server will see the Client IP Address with SNAT Enabled is using X-Forward.

     

     

    Think of SNAT as the man in the middle. Client only knows about the Virtual Server and the Pool Server only knows about the Virtual Server. Client and Pool server never know about one another (without X-Forward).