Hi all,
I just started a new role looking after a Network where not too long before I started had a complete Internet Edge redesign. It seems that FTP transactions destined to the Internet haven't been working since the changes.
Until yesterday I had no idea about the history of FTP and why it needs special attention. i.e. 'Active' mode won't work with NAT and 'Passive' mode requires addtional ports to be opened on random high port numbers, and, without 'FTP inspection' enabled via a service policy, requires those 'random' port numbers to be opened outbound on the Firewall.
Long story short I found a 'tcp-bypass' class map located under the global policy which seemed to be bypassing the state tracking for ALL TCP. When I remove this class map from the global policy, FTP works!! I suspect this is due to the global policy using the class 'inspection_default' where FTP is being inspected and allowing the FTP client to connect to the server on those random port numbers that it requires. However I have no idea if removing the -tcp-bypass' class map is breaking any other TCP sessions, or why it was implemented in the first place.
Correct me if I'm wrong (because a lot of this is new to me), but shouldn't the global policy match and action the 'inspection_default' map before it processes the 'tcp-bypass' map?
My config is below...
class-map tcp-bypass
match access-list tcp-bypass
class-map PROXY-STATE-BYPASS
match access-list tcp-bypass
class-map inspection_default
match default-inspection-traffic
!
!
policy-map type inspect dns preset_dns_map
parameters
message-length maximum client auto
message-length maximum 512
policy-map global_policy
class inspection_default
inspect dns preset_dns_map
inspect ftp
inspect h323 h225
inspect h323 ras
inspect rsh
inspect rtsp
inspect esmtp
inspect sqlnet
inspect skinny
inspect sunrpc
inspect xdmcp
inspect sip
inspect netbios
inspect tftp
inspect ip-options
class tcp-bypass
set connection advanced-options tcp-state-bypass
class class-default
user-statistics accounting
policy-map PROXY-STATE-BYPASS-PMAP
class PROXY-STATE-BYPASS
set connection advanced-options tcp-state-bypass
!
service-policy global_policy global
Any help/advice would be greatly appreciated!!
Brett
ps. There are no service policies applied to any of the ASA's interfaces.
