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ASA NAT Strange ISSUE

I have configured 2 ISP on ASA 5505 which is using IP SLA to track internet connection . Following is Static NAT configuration

static (inside,outside) tcp ISPA_Second_IP 3389 Jonas 3389 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Third_IP 3389 192.168.10.7 3389 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Third_IP 9983 192.168.10.20 3389 netmask 255.255.255.255

static (inside,outside) tcp ISPA_FIRST_IP smtp Exchange smtp netmask 255.255.255.255

static (inside,outside) tcp ISPA_FIRST_IP 3389 Exchange 3389 netmask 255.255.255.255

static (inside,outside) udp ISPA_Second_IP 1434 Jonas 1434 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Second_IP ftp Jonas ftp netmask 255.255.255.255

static (inside,outside) tcp ISPA_Second_IP 1433 Exchange 1433 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Second_IP 1434 Exchange 1434 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Second_IP 50000 192.168.10.200 50000 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Second_IP 5001 192.168.10.200 5001 netmask 255.255.255.255

static (inside,outside) tcp ISPA_Second_IP 8192 192.168.10.202 8192 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_First_IP https Exchange https netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP 3389 Jonas 3389 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_third_IP 3389 192.168.10.7 3389 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_third_IP 9983 192.168.10.20 3389 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_First_IP smtp Exchange smtp netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_First_IP 3389 Exchange 3389 netmask 255.255.255.255

static (inside,WAN_Failover) udp ISPB_Second_IP 1434 Jonas 1434 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP ftp Jonas ftp netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP 1433 Exchange 1433 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP 1434 Exchange 1434 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP 50000 192.168.10.200 50000 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP 5001 192.168.10.200 5001 netmask 255.255.255.255

static (inside,WAN_Failover) tcp ISPB_Second_IP 8192 192.168.10.202 8192 netmask 255.255.255.255

static (inside,outside) tcp ISPA_FIRST_IP www Exchange www netmask 255.255.255.255

static (inside,outside) tcp ISPA_FIRST_IP https Exchange https netmask 255.255.255.255


I have configured that ISPA first IP to the port 80 of Exchange as you can see but that doesnt seems to work fine , All NAT configs were duplicate which means if Exchange server is PAT to ISP_A at the same time it is for ISP_B , right now I have removed rule for ISP_B exchange just for troubleshooting purpose .

packet-tracer input outside tcp 4.2.2.2 80 ISPA_First_IP 80

Phase: 1

Type: UN-NAT

Subtype: static

Result: ALLOW

Config:

static (inside,outside) tcp ISPA_First_IP www Exchange www netmask 255.255.255.255

  match tcp inside host Exchange eq 80 outside any

    static translation to ISPA_First_IP/80

    translate_hits = 0, untranslate_hits = 5

Additional Information:

NAT divert to egress interface inside

Untranslate ISPA_First_IP/80 to Exchange/80 using netmask 255.255.255.255

Phase: 2

Type: ROUTE-LOOKUP

Subtype: input

Result: ALLOW

Config:

Additional Information:

in   0.0.0.0         0.0.0.0         outside

Phase: 3

Type: ACCESS-LIST

Subtype: log

Result: ALLOW

Config:

access-group inbound in interface outside

access-list inbound extended permit tcp any host ISPA_First_IP eq www

Additional Information:

Phase: 4

Type: IP-OPTIONS

Subtype:

Result: ALLOW

Config:

Additional Information:

Phase: 5

Type: FOVER

Subtype: standby-update

Result: ALLOW

Config:

Additional Information:

Phase: 6

Type: HOST-LIMIT

Subtype:

Result: ALLOW

Config:

Additional Information:

Phase: 7

Type: NAT

Subtype: rpf-check

Result: ALLOW

Config:

static (inside,outside) tcp ISPA_First_IP www Exchange www netmask 255.255.255.255

  match tcp inside host Exchange eq 80 outside any

    static translation to ISPA_First_IP/80

    translate_hits = 0, untranslate_hits = 5

Additional Information:

Phase: 8

Type: NAT

Subtype: host-limits

Result: ALLOW

Config:

static (inside,outside) tcp ISPA_First_IP smtp Exchange smtp netmask 255.255.255.255

  match tcp inside host Exchange eq 25 outside any

    static translation to ISPA_First_IP/25

    translate_hits = 1, untranslate_hits = 0

Additional Information:

Phase: 9

Type: IP-OPTIONS

Subtype:

Result: ALLOW

Config:

Additional Information:

Phase: 10

Type: FLOW-CREATION

Subtype:

Result: ALLOW

Config:

Additional Information:

New flow created with id 8137, packet dispatched to next module

Result:

input-interface: outside

input-status: up

input-line-status: up

output-interface: inside

output-status: up

output-line-status: up

Action: allow


I cant access that server from outside but as you can see in packet tracer command in Phase 7 it shows port 80 but in phase 8 it shows SMTP which is quite strange .

Is that a hardware issue ?

1 Reply 1

varrao
Level 10
Level 10

Take captures on the ingress and egress interfaces, it would tell you which side is not responding.

https://supportforums.cisco.com/docs/DOC-17814

Thanks,
Varun Rao
Security Team,
Cisco TAC

Thanks,
Varun Rao
Review Cisco Networking products for a $25 gift card