DMZ to Public - Deny TCP (no connection)

[kostergard]

I have a web server setup in a DMZ network off an ASA 5505 base license. I am aware that no traffic can be passed from the internal VLAN to the DMZ VLAN, however my issue lies in passing traffic from the DMZ to the public interface.

Static PAT is configured for the DMZ web server to the public interface on Port 80.

It appears the connection works correctly until the server goes to return data - at which point the following shows:

Deny TCP (no connection) from DMZ IP/80 to PUBLIC/Port flags SYN ACK on interface inside.

I don't have any idea why it is even touching the inside interface, and I've reset the configuration numerous times and started over trying to get this to work.

If I do a static PAT from outside to the internal VLAN, everything works fine, it's just something about the DMZ.

Any help that anyone could provide would be greatly appreciated, this has been more than frustrating.

Thanks,

Kris

CONFIG:

ASA Version 7.2(4)
!
hostname bricks
names
!
interface Vlan1
nameif inside
security-level 100
ip address 192.168.5.1 255.255.255.0
!
interface Vlan2
nameif outside
security-level 0
ip address x.x.x.x 255.255.255.224
!
interface Vlan3
no forward interface Vlan1
nameif dmz
security-level 50
ip address 172.16.5.1 255.255.255.0
!
interface Ethernet0/0
switchport access vlan 2
!
interface Ethernet0/1
!
interface Ethernet0/2
!
interface Ethernet0/3
!
interface Ethernet0/4
!
interface Ethernet0/5
switchport access vlan 3
!
interface Ethernet0/6
switchport access vlan 3
!
interface Ethernet0/7
switchport access vlan 3
!
ftp mode passive
dns server-group DefaultDNS
same-security-traffic permit intra-interface
access-list inside_access_in extended permit ip any any
access-list outside_access_in extended permit tcp any interface outside eq www
access-list dmz_access_in extended permit ip any any
pager lines 24
logging enable
logging asdm informational
mtu inside 1500
mtu outside 1500
mtu dmz 1500
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-524.bin
no asdm history enable
arp timeout 14400
nat-control
global (outside) 1 interface
nat (inside) 1 0.0.0.0 0.0.0.0
static (dmz,outside) tcp interface

http://www 172.16.5.21

http://www netmask

255.255.255.255
access-group inside_access_in in interface inside
access-group outside_access_in in interface outside
access-group dmz_access_in in interface dmz
route outside 0.0.0.0 0.0.0.0 70.169.153.193 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
http server enable
http 192.168.5.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
client-update enable
telnet timeout 5
ssh timeout 5
console timeout 0
dhcpd auto_config outside
!
dhcpd address 192.168.5.240-192.168.5.254 inside
dhcpd dns 192.168.5.20 4.2.2.1 interface inside
dhcpd wins 192.168.5.20 interface inside
dhcpd enable inside
!

!
class-map inspection_default
match default-inspection-traffic
!
!
policy-map type inspect dns preset_dns_map
parameters
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
!
service-policy global_policy global
prompt hostname context

 

[Supergrrover]

Try adding
nat (dmz) 1 0.0.0.0 0.0.0.0



Brent
Systems Engineer / Consultant
CCNP, CCSP

 

[kostergard]

Unfortunately, still no joy. I recieve the same error after adding the dynamic NAT for the DMZ.

Deny TCP (no connection) from 172.16.5.21/80 to x.x.x.x/9791 flags SYN ACK on interface inside

The config is the same as above, just added the following:

nat (dmz) 1 0.0.0.0 0.0.0.0

Any other suggestions? I really appreciate the help.

-Kris

 

[Supergrrover]

What is the default gateway on the server? Double check to make sure you don't have the inside gateway on it.


Brent
Systems Engineer / Consultant
CCNP, CCSP