Thursday, January 30, 2020

ASA5506 1-to-1 NAT Problem

Hi All,

I have an ASA 5506, connected to 100Mbps Comcast fiber. The public network is 50.xxx.xx.232 /29. Comcast router is 50.xxx.xx.233, and my outside port on ASA is 50.xxx.xx.234. I have three CCTV DVR's in a DMZ on the ASA using LAN IP's 192.168.1.250, 192.168.1.251 and 192.168.1.252. I am static NATing them to 50.xxx.xx.236, 50.xxx.xx.237 and 50.xxx.xx.238 respectively. After making the configurations on the ASA, I cannot ping or access these devices on the above 1-to-1 NATed IP's from the internet. What's more is if I change the public IP of the outside interface of my ASA to something else on the /29 subnet (50.xxx.xx.235 for example), I have no connectivity. But as long as I use 50.xxx.xx.234, I have internet connection.

Packet-tracer tests are passing without a problem when targeting the IP's I'm using for the NATing on the /29. I am starting to suspect ISP as the culprit, but could use some opinions. I've replaced the ASA with two other units - one 5506 and one 5505. Same results each time. Below is the config, followed by packet-tracer.

interface GigabitEthernet1/4

description To_Zonet_ZFS3024_Unmanaged_Switch_Port_24

nameif DMZ

security-level 50

ip address 192.168.1.1 255.255.255.0

!

object network CCTV-DVR-1

host 192.168.1.250

object network CCTV-DVR-2

host 192.168.1.251

object network CCTV-DVR-3

host 192.168.1.252

object network CCTV-DVR-1-p

host 50.xxx.xx.236

object network CCTV-DVR-2-p

host 50.xxx.xx.237

object network CCTV-DVR-3-p

host 50.xxx.xx.238

!

object network CCTV-DVR-1

nat (DMZ,outside) static CCTV-DVR-1-p

object network CCTV-DVR-2

nat (DMZ,outside) static CCTV-DVR-2-p

object network CCTV-DVR-3

nat (DMZ,outside) static CCTV-DVR-3-p

Packet Tracer from outside source, inbound to DVR 50.xxx.xx.236:

FW14-SH5506-A# packet-tracer input outside tcp 12.x.xxx.20 8000 50.xxx.xx.236 8000

Phase: 1

Type: UN-NAT

Subtype: static

Result: ALLOW

Config:

object network CCTV-DVR-1

nat (DMZ,outside) static CCTV-DVR-1-p

Additional Information:

NAT divert to egress interface DMZ

Untranslate 50.xxx.xx.236/8000 to 192.168.1.250/8000

Phase: 2

Type: ACCESS-LIST

Subtype: log

Result: ALLOW

Config:

access-group outside_access_in in interface outside

access-list outside_access_in extended permit tcp any object-group Camera-DVRs object-group CameraPorts

object-group network Camera-DVRs

network-object object CCTV-DVR-1

network-object object CCTV-DVR-2

network-object object CCTV-DVR-3

object-group service CameraPorts tcp

port-object eq www

port-object eq 81

port-object eq 82

port-object eq 1024

port-object eq 1025

port-object eq 1026

port-object eq 8000

port-object eq 8001

port-object eq 8002

Additional Information:

Phase: 3

Type: NAT

Subtype: per-session

Result: ALLOW

Config:

Additional Information:

Phase: 4

Type: IP-OPTIONS

Subtype:

Result: ALLOW

Config:

Additional Information:

Phase: 5

Type: VPN

Subtype: ipsec-tunnel-flow

Result: ALLOW

Config:

Additional Information:

Phase: 6

Type: NAT

Subtype: rpf-check

Result: ALLOW

Config:

object network CCTV-DVR-1

nat (DMZ,outside) static CCTV-DVR-1-p

Additional Information:

Phase: 7

Type: NAT

Subtype: per-session

Result: ALLOW

Config:

Additional Information:

Phase: 8

Type: IP-OPTIONS

Subtype:

Result: ALLOW

Config:

Additional Information:

Phase: 9

Type: FLOW-CREATION

Subtype:

Result: ALLOW

Config:

Additional Information:

New flow created with id 9405, packet dispatched to next module

Result:

input-interface: outside

input-status: up

input-line-status: up

output-interface: DMZ

output-status: up

output-line-status: up

Action: allow

Trace routes to 50.xxx.xx.234 (ASA WAN IP) make it one hop further than trace routes to any of the IP's I am trying to use for the CCTV NATing.

Has to be ISP right? Question is, what could they be doing to it? It was working fine this morning.



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