Helloo All,
This has to be the most weirdest issue I have seen since the past year on my ASA.
I have an ASA 5540 running the 8.4(2) code without any issues until I stumbled upon this problem last week and I have spent sleepless nights with no resolution! So, take a deep breath and here is a brief description of my setup and the problem:
A Simple IPSEC tunnel between my ASA 5540 8.4(2) and a Juniper SSG 140 screen OS 6.3.0r9.0(route based VPN)
The tunnel comes up without any issues but the ASA refuses to encrypt the traffic but decrypts it with GLORY!
below are some debug outputs, show outputs and a packet tracer output which also has an explanation of my WEIRD NAT issue:
my setup - ( I wont get into the tunnel encryption details as my tunnel negotiations are perfect and comes up right off the bat when the ASA is configured as answer only)
CISCO ASA - IPSec networking details
LOCAL NETWORK - 10.2.4.0/28
REMOTE NETWORK - 192.168.171.8/32
JUNIPER SSG 140 - IPSec networking details
PROXY ID:
LOCAL NETWORK - 192.168.171.8/32
REMOTE NETWORK - 10.2.4.0/28
HOSTNAME# sh cry ipsec sa peer <JUNIPER SSG PEER>
peer address: <JUNIPER SSG PEER>
Crypto map tag: outside_map, seq num: 5, local addr: <local peer>
access-list outside_cryptomap_4 extended permit ip 10.2.4.0 255.255.255.240 host 192.168.171.8
local ident (addr/mask/prot/port): (10.2.4.0/255.255.255.240/0/0)
remote ident (addr/mask/prot/port): (192.168.171.8/255.255.255.255/0/0)
current_peer: <JUNIPER SSG PEER>
#pkts encaps: 0, #pkts encrypt: 0, #pkts digest: 0
#pkts decaps: 72, #pkts decrypt: 72, #pkts verify: 72
#pkts compressed: 0, #pkts decompressed: 0
#pkts not compressed: 0, #pkts comp failed: 0, #pkts decomp failed: 0
#pre-frag successes: 0, #pre-frag failures: 0, #fragments created: 0
#PMTUs sent: 0, #PMTUs rcvd: 0, #decapsulated frgs needing reassembly: 0
#send errors: 0, #recv errors: 0
local crypto endpt.: <local peer>/0, remote crypto endpt.: <juniper remote peer>/0
path mtu 1500, ipsec overhead 58, media mtu 1500
current outbound spi: 5041C19F
current inbound spi : 0EC13558
inbound esp sas:
spi: 0x0EC13558 (247543128)
transform: esp-3des esp-sha-hmac no compression
in use settings ={L2L, Tunnel, }
slot: 0, conn_id: 22040576, crypto-map: outside_map
sa timing: remaining key lifetime (sec): 3232
IV size: 8 bytes
replay detection support: Y
Anti replay bitmap:
0xFFFFFFFF 0xFFFFFFFF
outbound esp sas:
spi: 0x5041C19F (1346486687)
transform: esp-3des esp-sha-hmac no compression
in use settings ={L2L, Tunnel, }
slot: 0, conn_id: 22040576, crypto-map: outside_map
sa timing: remaining key lifetime (sec): 3232
IV size: 8 bytes
replay detection support: Y
Anti replay bitmap:
0x00000000 0x00000001
VPN CONTEXTS for this IPSEC tunnel:
HOSTNAME# sh asp table vpn-context det
VPN CTX = 0x0742E6BC
Peer IP = 192.168.171.8
Pointer = 0x78C94BF8
State = UP
Flags = ENCR+ESP
SA = 0x9C28B633
SPI = 0x5041C19D
Group = 0
Pkts = 0
Bad Pkts = 0
Bad SPI = 0
Spoof = 0
Bad Crypto = 0
Rekey Pkt = 0
Rekey Call = 0
VPN Filter = <none>
VPN CTX = 0x07430D3C
Peer IP = 192.168.1.8
Pointer = 0x78F62018
State = UP
Flags = DECR+ESP
SA = 0x9C286E3D
SPI = 0x9B6910C5
Group = 1
Pkts = 297
Bad Pkts = 0
Bad SPI = 0
Spoof = 0
Bad Crypto = 0
Rekey Pkt = 0
Rekey Call = 0
VPN Filter = <none>
access-list outside_cryptomap_4 extended permit ip 10.2.4.0 255.255.255.240 host 192.168.171.8
nat (inside,outside) source static Ren-vers Ren-vers destination static Peer-Host Peer-Host no-proxy-arp route-lookup
object network Ren-vers
subnet 10.2.4.0 255.255.255.240
object network Peer-Host
host 192.168.171.8
sh cry ipsec sa
IKE Peer: <remote peer>
Type : L2L Role : responder
Rekey : no State : MM_ACTIVE
packet tracer output extract for a packet being sent from the 10.2.4.0/28 network to 192.168.171.8 host
Phase: 7
Type: VPN
Subtype: encrypt
Result: ALLOW
Config:
Additional Information:
Forward Flow based lookup yields rule:
out id=0x7789d788, priority=70, domain=encrypt, deny=false
hits=2, user_data=0x742e6bc, cs_id=0x7ba38680, reverse, flags=0x0, protocol=0
src ip/id=10.2.4.0, mask=255.255.255.240, port=0
dst ip/id=192.168.171.8, mask=255.255.255.255, port=0, dscp=0x0
input_ifc=any, output_ifc=outside
THE VPN contexts match for the encrytpion+encapsulation and the hits here increment only when I run a packet tracer test from my inside host to the remote peer.
A Full packet tracer output for a packet from the 10.2.4.1 255.255.255.255 network to host 192.168.171.8:
Phase: 1
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Config:
Implicit Rule
Additional Information:
Forward Flow based lookup yields rule:
in id=0x77ebd1b0, priority=1, domain=permit, deny=false
hits=3037156, user_data=0x0, cs_id=0x0, l3_type=0x8
src mac=0000.0000.0000, mask=0000.0000.0000
dst mac=0000.0000.0000, mask=0100.0000.0000
input_ifc=inside, output_ifc=any
Phase: 2
Type: ROUTE-LOOKUP
Subtype: input
Result: ALLOW
Config:
Additional Information:
in 192.168.171.0 255.255.255.0 outside
Phase: 3
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Forward Flow based lookup yields rule:
in id=0x77ec1030, priority=0, domain=inspect-ip-options, deny=true
hits=212950, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=0
src ip/id=0.0.0.0, mask=0.0.0.0, port=0
dst ip/id=0.0.0.0, mask=0.0.0.0, port=0, dscp=0x0
input_ifc=inside, output_ifc=any
Phase: 4
Type:
Subtype:
Result: ALLOW
Config:
Additional Information:
Forward Flow based lookup yields rule:
in id=0x7c12cb18, priority=18, domain=flow-export, deny=false
hits=172188, user_data=0x78b1f438, cs_id=0x0, use_real_addr, flags=0x0,
src ip/id=0.0.0.0, mask=0.0.0.0, port=0
dst ip/id=0.0.0.0, mask=0.0.0.0, port=0, dscp=0x0
input_ifc=inside, output_ifc=any
Phase: 5
Type: NAT
Subtype:
Result: ALLOW
Config:
nat (inside,outside) source static Ren-vers Ren-vers destination static Peer-Host Peer-Host no-proxy-arp route-lookup
Additional Information:
Static translate 10.2.4.1/2700 to 10.2.4.1/2700
Forward Flow based lookup yields rule:
in id=0x77e0a878, priority=6, domain=nat, deny=false
hits=9, user_data=0x7b7360a8, cs_id=0x0, use_real_addr, flags=0x0, proto
src ip/id=10.2.4.1, mask=255.255.255.240, port=0
dst ip/id=192.168.171.8, mask=255.255.255.255, port=0, dscp=0x0
input_ifc=inside, output_ifc=outside
(this is the weird NAT issue I am seeing. I see the hits count is incrementing only when I run the packet tracer even thugh I have constant pings(traffic) from the 192.168.171.8 host to the 10.2.4.1/28) - please see the packet capture that i have pasted after this section)
Phase: 6
Type: VPN
Subtype: encrypt
Result: ALLOW
Config:
Additional Information:
Forward Flow based lookup yields rule:
out id=0x7b8751f8, priority=70, domain=encrypt, deny=false
hits=3, user_data=0x7432b74, cs_id=0x7ba38680, reverse, flags=0x0, proto
src ip/id=10.2.4.1, mask=255.255.255.240, port=0
dst ip/id=192.168.171.8, mask=255.255.255.255, port=0, dscp=0x0
input_ifc=any, output_ifc=outside
Phase: 7
Type: VPN
Subtype: ipsec-tunnel-flow
Result: ALLOW
Config:
Additional Information:
Reverse Flow based lookup yields rule:
in id=0x78b0c280, priority=69, domain=ipsec-tunnel-flow, deny=false
hits=154, user_data=0x7435f94, cs_id=0x0, reverse, flags=0x0, protocol=0
src ip/id=192.168.171.8, mask=255.255.255.255, port=0
dst ip/id=10.2.4.1, mask=255.255.255.240, port=0, dscp=0x0
input_ifc=outside, output_ifc=any
Phase: 8
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Reverse Flow based lookup yields rule:
in id=0x77e7a510, priority=0, domain=inspect-ip-options, deny=true
hits=184556, user_data=0x0, cs_id=0x0, reverse, flags=0x0, protocol=0
src ip/id=0.0.0.0, mask=0.0.0.0, port=0
dst ip/id=0.0.0.0, mask=0.0.0.0, port=0, dscp=0x0
input_ifc=outside, output_ifc=any
Phase: 9
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Config:
Additional Information:
New flow created with id 119880921, packet dispatched to next module
Module information for forward flow ...
snp_fp_tracer_drop
snp_fp_inspect_ip_options
snp_fp_tcp_normalizer
snp_fp_translate
snp_fp_adjacency
snp_fp_encrypt
snp_fp_fragment
snp_ifc_stat
Module information for reverse flow ...
snp_fp_tracer_drop
snp_fp_inspect_ip_options
snp_fp_ipsec_tunnel_flow
snp_fp_translate
snp_fp_tcp_normalizer
snp_fp_adjacency
snp_fp_fragment
snp_ifc_stat
Result:
input-interface: inside
input-status: up
input-line-status: up
output-interface: outside
output-status: up
output-line-status: up
Action: allow
HOSTNAME# sh cap cap1
8 packets captured
1: 12:26:53.376033 192.168.10.252 > 10.2.4.1: icmp: echo request
2: 12:26:53.376597 10.2.4.1 > 192.168.10.252: icmp: echo reply
3: 12:26:56.487905 192.168.171.8 > 10.2.4.1: icmp: echo request
4: 12:27:01.489217 192.168.171.8 > 10.2.4.1: icmp: echo request
5: 12:27:03.378245 192.168.10.252 > 10.2.4.1: icmp: echo request
6: 12:27:03.378825 10.2.4.1 > 192.168.10.252: icmp: echo reply
7: 12:27:06.491597 192.168.171.8 > 10.2.4.1: icmp: echo request
8: 12:27:11.491856 192.168.171.8 > 10.2.4.1: icmp: echo request
8 packets shown
As you can see, there is no echo reply packet at all as the packet is not being encapsulated while it is being sent back.
I have been going madddd with this. Also, this is a live production multitenant firewall with no issues at all apart from this ipsec tunnel to a juniper!!
Also, the 192.168.10.0/24 is another IPSec tunnel remote network to this 10.2.4.0/28 network and this IPSEC tunnel has a similar Juniper SSG 140 screen os 6.3.0r9.0 at the remote end and this woks like a charm without any issues, but the 171 is not being encrypted by the ASA at all.
If anybody could help me out, that would be greatt and greatly appreciated!!
Thanks heaps.!
