From: Stephen Vallois-Davies (cisco@lockdown.nu)
Date: Mon May 01 2006 - 13:49:28 ART
Hi All,
I was setting up some NAT, and came across an odd intermittent traffic
throughput problem.
The setup is as follows:
PC2 ------------- R5 ------------------ PC1
F0/0 f0/1.999 vlan 999
PC2 = 1.10.10.4
pc1 = 128.1.5.1
With R5 having the following config:
interface FastEthernet0/0
ip address 1.10.11.249 255.255.254.0
ip nat inside
!
interface FastEthernet0/1.999
encapsulation dot1Q 999
ip address 128.1.5.5 255.255.255.0
ip nat outside
!
ip route 1.10.13.250 255.255.255.255 128.1.5.1
ip route 128.1.6.0 255.255.255.0 FastEthernet0/0
!
ip nat inside source static 1.10.10.4 128.1.6.254
ip nat outside source static 128.1.5.1 1.10.13.250
!
If the route for the outside global addresses is a host
route to PC2, then traffic will flow between PC1 and PC2
However if the route is as follows:
ip route 1.10.13.250 255.255.255.255 f0/1.999
then the packet throughput is intermittent. With a ping from
PC1 to PC2, PC2 will always send the echo request to PC1 as follows:
1.10.10.4 -> 1.10.13.250
but then R5 has a problem forwarding/translating the packet.
Arp entries, nat entries all look good. Any ideas?
For the outside->inside translation I can use a host as destination for
route, or interface, and translation is unaffected.
It only seems to be a problem for the 'ip nat outside' configurations.
Cheers, Steve.
This archive was generated by hypermail 2.1.4 : Thu Jun 01 2006 - 06:33:20 ART