NAT & Routing

slopes · ‎03-11-2010

Hi Guys,

we have problem with NAT/Routing if its asymmetric ,when we initiate a FTP from client eg we have two router doing HSRP and two WAN Links,

the traffic initiate from Client behind RouterA (Active on HSRP) but due to WAN Failure,the traffic goes via RouterB WAN Link,these two routers have a interlink between them.so the NAT happens on RouterA and routing happens on RouterB and due this the FTP transfer fails.

Any suggestion please do response with your valuable suggestion.

Rgds

Sanjeev

sanjivlsg@yahoo.com

Ganesh Hariharan · ‎03-11-2010

Hi Guys,

we have problem with NAT/Routing if its asymmetric ,when we initiate a FTP from client eg we have two router doing HSRP and two WAN Links,

the traffic initiate from Client behind RouterA (Active on HSRP) but due to WAN Failure,the traffic goes via RouterB WAN Link,these two routers have a interlink between them.so the NAT happens on RouterA and routing happens on RouterB and due this the FTP transfer fails.

Any suggestion please do response with your valuable suggestion.

Rgds

Sanjeev

Hi Sanjeev,

For TCP based application you need to have persistency between client and server as traffic is getting distrubed while transfer then ftp will definetly get failed.

Hope to help !!

Ganesh.H

Gian Paolo · ‎03-12-2010

What about HSRP interface track & preemption?

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094e8c.shtml

When WAN goes down on R1 then R2 becomes active and does NAT+Routing so without asymmetric routing FTP work.

HTH