A. active/active firewall setup ) X# t3 H- [" }1 ^9 ?$ q, ^B. single path in and out of the network.3 J( p; f/ {7 u: O t' d5 e% @& f
C. active/standby firewall setup) v, |6 ?$ b6 x- H; l# Z" i
D. redundant routers running VRRP
国外论坛也在讨论这道题,给出的答案是D.( C1 N8 e+ b4 D) u) w
Asymmetric routing is the scenario in which outing packet is through a path, returning packet is through another path. VRRP can cause asymmetric routing occur,9 {: t D# P/ v6 n
for example: 1 X0 e# V. U* y8 U* v* }' W6 MR1 and R2 are the two routers in the local internal LAN network that are running VRRP. R1 is the master router and R2 is the backup router. ( O- e5 y! r9 z' l8 z% kThese two routers are connected to an ISP gateway router, by using BGP. This topology provides two possible outgoing and incoming paths for the traffic.9 @! Y) n1 S4 K- T
Suppose the outgoing traffic is sent through R1 but VRRP failover occurs, R2 becomes the new master router -> traffic passing through R2 instead ->asymmetric routing occurs.