topic Re: Cannot Ping Without Source in Network Security

Cannot Ping Without Source

jtmullis82 — Mon, 11 Mar 2019 17:50:02 GMT

I have a router behind a Cisco ASA 5520. The router has interfaces which are carried on 2 seperate Crypto maps going to the same peer. I can ping across one of the interfaces but when I try to ping across the other it appears to be using the other Cryptomap so it doesnt find its way. If I ping and specify the source it uses the correct crypto map and works fine. i have a static route built telling it which interface to use but still with no luck. How can i force it to use the correct cryptomap ?

Re: Cannot Ping Without Source

jtmullis82 — Mon, 24 May 2010 22:18:26 GMT

Im sorry, It is the same cryptomap but with 2 different access-lists for the seperate subnets.

Re: Cannot Ping Without Source

Federico Coto Fajardo — Mon, 24 May 2010 22:19:56 GMT

Joseph,

You have one crypto map on the ASA and connecting to two interfaces on the router?

What's exactly the problem that you're having? Could you elaborate a bit?

Federico.

Re: Cannot Ping Without Source

jtmullis82 — Mon, 24 May 2010 22:41:43 GMT

Below are the two access-lists i have built going over cryptomap 2. i have a router that has a IP of 10.1.25.251 and i can successfully ping the router on the other end which is 10.1.26.1. on the same router that has the 10.1.25.251 address i have a IP of 10.10.10.5 and when i try to ping the other end which is 10.10.30.6 it doesnt work. i ran a icmp trace on the ASA it sources from the inside 10.1.25.251. but when i do ping 10.10.30.6 source 10.10.10.5 the icmp trace shows the source as inside 10.10.10.5 and it works. not sure how to correct this. i have a static route telling anything 10.10.30.0/24 to route to 10.10.10.1 but still need to use source.

!! ACCESS - LISTS !!

access-list outside_2_cryptomap extended permit ip 10.10.10.0 255.255.255.0 10.10.30.0 255.255.255.0
access-list outside_2_cryptomap extended permit ip 10.1.25.0 255.255.255.0 10.1.26.0 255.255.255.0

Re: Cannot Ping Without Source

Federico Coto Fajardo — Mon, 24 May 2010 22:50:50 GMT

Joseph,

Please correct me if i'm wrong....

The networks on the router behind the ASA are:

10.1.25.x

10.10.10.x

There's a VPN tunnel where you can PING from 10.1.25.251 to 10.1.26.1

My question is:

When you attempt to PING to 10.10.30.6 from 10.10.10.5... is this a different VPN tunnel? I mean a tunnel to a different location?

I see that you have a route to 10.10.30.x pointing to 10.10.10.1

This means that is indeed another tunnel, so you should have both statements in a different ACL.

If this two examples go to different VPN tunnels, both lines of the ACL should belong to a separate ACL because they belong to a different peer.

If you want, you can post the configuration.

Federico.

Re: Cannot Ping Without Source

jtmullis82 — Mon, 24 May 2010 23:08:04 GMT

they are going to the same location on the same peer. the router on the other side ( which is behind a ASA5510 ) has the 10.1.26.1 address and also the 10.10.30.6. so i have one cryptomap going to one peer but 2 ACL's on it. i cannot get the prints for the other end until tomorrow but here are some prints from my local end.

!! ASA SHOW RUN !!

YPG-ASA5520-1# show run
: Saved
:
ASA Version 8.2(1)
!
hostname YPG-ASA5520-1
enable password xeWGH4eCU0N7TfVY encrypted
passwd xeWGH4eCU0N7TfVY encrypted
names
name 10.1.25.18 test
!
interface GigabitEthernet0/0
nameif outside
security-level 0
ip address 6.7.0.13 255.255.254.0
!
interface GigabitEthernet0/1
nameif internal
security-level 0
ip address 10.0.2.166 255.255.255.0
!
interface GigabitEthernet0/2
shutdown
no nameif
no security-level
no ip address
!
interface GigabitEthernet0/3
nameif inside
security-level 100
ip address 10.10.10.1 255.255.255.0
!
interface Management0/0
nameif management
security-level 100
ip address 192.168.1.1 255.255.255.0
management-only
!
access-list 100 extended permit ip any any
access-list outside_1_cryptomap extended permit ip 10.10.10.0 255.255.255.0 10.10.20.0 255.255.255.0
access-list outside_2_cryptomap extended permit ip 10.10.10.0 255.255.255.0 10.10.30.0 255.255.255.0
access-list outside_2_cryptomap extended permit ip 10.1.25.0 255.255.255.0 10.1.26.0 255.255.255.0
access-list outside_3_cryptomap extended permit ip 10.10.10.0 255.255.255.0 10.10.40.0 255.255.255.0
pager lines 24
logging enable
logging buffered debugging
logging asdm informational
mtu outside 1500
mtu internal 1500
mtu inside 1500
mtu management 1500
no failover
icmp unreachable rate-limit 1 burst-size 1
asdm image disk0:/asdm-621.bin
no asdm history enable
arp timeout 14400
access-group 100 in interface outside
route outside 0.0.0.0 0.0.0.0 6.7.0.1 1
route inside 10.1.25.0 255.255.255.0 10.10.10.5 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
timeout tcp-proxy-reassembly 0:01:00
dynamic-access-policy-record DfltAccessPolicy
http server enable
http 192.168.1.0 255.255.255.0 management
http 10.0.2.0 255.255.255.0 inside
http 10.0.2.0 255.255.255.0 internal
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
crypto ipsec transform-set ESP-DES-SHA esp-des esp-sha-hmac
crypto ipsec security-association lifetime seconds 28800
crypto ipsec security-association lifetime kilobytes 4608000
crypto map outside_map 1 match address outside_1_cryptomap
crypto map outside_map 1 set peer 140.32.167.58
crypto map outside_map 1 set transform-set ESP-DES-SHA
crypto map outside_map 2 match address outside_2_cryptomap
crypto map outside_map 2 set peer 140.32.171.2
crypto map outside_map 2 set transform-set ESP-DES-SHA
crypto map outside_map 3 match address outside_3_cryptomap
crypto map outside_map 3 set peer 131.120.38.2
crypto map outside_map 3 set transform-set ESP-DES-SHA
crypto map outside_map interface outside
crypto isakmp enable outside
crypto isakmp policy 10
authentication pre-share
encryption des
hash sha
group 5
lifetime 86400
telnet timeout 5
ssh 0.0.0.0 0.0.0.0 outside
ssh 0.0.0.0 0.0.0.0 inside
ssh timeout 60
ssh version 2
console timeout 0
dhcpd address 192.168.1.2-192.168.1.254 management
dhcpd enable management
!
threat-detection basic-threat
threat-detection statistics access-list
no threat-detection statistics tcp-intercept
webvpn
tunnel-group 140.32.167.58 type ipsec-l2l
tunnel-group 140.32.167.58 ipsec-attributes
pre-shared-key *
tunnel-group 140.32.171.2 type ipsec-l2l
tunnel-group 140.32.171.2 ipsec-attributes
pre-shared-key *
tunnel-group 131.120.38.2 type ipsec-l2l
tunnel-group 131.120.38.2 ipsec-attributes
pre-shared-key *
!
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
Cryptochecksum:69ef98a4d8ac38ebbdca0631b4932ba6
: end

!! ROUTER'S SHOW ROUTER INTERFACES !!

===============================================================================
Interface Table (Router: Base)
===============================================================================
Interface-Name                   Adm         Opr         Mode    Port/SapId
   IP-Address                                                    PfxState
-------------------------------------------------------------------------------
system                           Up          Up          Network system
   10.1.25.251/32                                                n/a
to-5520                          Up          Up          Network 1/1/8
   10.10.10.5/24                                                 n/a
to-7750A                         Up          Up          Network 1/1/7
   10.1.32.74/30                                                 n/a
-------------------------------------------------------------------------------
Interfaces : 3
===============================================================================

!! ROUTER'S SHOW STATIC ROUTES !!

===============================================================================
Static Route Table (Router: Base) Family: IPv4
===============================================================================
Prefix                                        Tag         Met    Pref Type Act
   Next Hop                                    Interface
-------------------------------------------------------------------------------
10.1.25.251/32                                0           1      5    NH   Y
   10.10.10.1                                  to-5520
10.1.25.252/32                                0           1      5    NH   Y
   10.1.32.73                                  to-7750A
10.1.26.0/24                                  0           1      5    NH   Y
   10.10.10.1                                  to-5520
10.10.30.0/24                                 0           1      5    NH   Y
   10.10.10.1                                  to-5520
-------------------------------------------------------------------------------
No. of Static Routes: 4
===============================================================================

Re: Cannot Ping Without Source

Federico Coto Fajardo — Mon, 24 May 2010 23:29:30 GMT

From the ASA's perspective, it will encrypt this traffic:

access-list outside_2_cryptomap extended permit ip 10.10.10.0 255.255.255.0 10.10.30.0 255.255.255.0
access-list outside_2_cryptomap extended permit ip 10.1.25.0 255.255.255.0 10.1.26.0 255.255.255.0

You mentioned that traffic from 10.1.25.x flows fine to 10.1.26.x

The problem is with traffic from 10.10.10.x to 10.10.30.x correct?

On the ASA, do a ''sh cry ips sa'' and check if you have an SA for those two networks.

Since traffic is flowing fine through the first line, you should see packets encrypted/decrypted, what about the second line?

Federico.

Re: Cannot Ping Without Source

jtmullis82 — Tue, 25 May 2010 13:34:35 GMT

When I ping from the router to 10.1.26.1 it works. It uses Cryptomap 2 and the ACL " access-list outside_2_cryptomap extended permit ip 10.1.25.0 255.255.255.0 10.1.26.0 255.255.255.0"

Here is the print from the ICMP TRACE on the ASA.

ICMP echo request from inside:10.1.25.251 to outside:10.1.26.1 ID=49375 seq=5 len=56

now on the same router i try to ping 10.10.30.6 which uses ACL " access-list outside_2_cryptomap extended permit ip 10.10.10.0 255.255.255.0 10.10.30.0 255.255.255.0" which is on the same cryptomap as you can see and going to the same peer. but when I initiate the ping from the router it sources it with the 10.1.25.251 address when it should source it from the boxes 10.10.10.5. this making me have to use " ping 10.10.30.6 source 10.10.10.5" when i try to ping from the box. here are the ICMP TRACE prints for this.

Here is what i get when i only use " ping 10.10.30.6 " This doesnt work

ICMP echo request from inside:10.1.25.251 to outside:10.10.30.6 ID=49376 seq=5 len=56

Here is what i get when i use " ping 10.10.30.6 source 10.10.10.5" This works

ICMP echo request from inside:10.10.10.5 to outside:10.10.30.6 ID=49377 seq=5 len=56

sorry i cannot show the full ICMP trace but the remote end router is currently turned off so it wont show it as working. the router will be turned back on shortly. so my question is how do i get it to use the correct ACL on the cryptomap without me having to use the SOURCE parameter on the print. i need to be able to just put the command " print 10.1.26.1" and " print 10.10.30.6" without source. as i stated before i have static routes telling this router to push 10.10.30.0/24 to 10.10.10.1 ( which is the inside interface of my ASA" But for some reason i still have to use source.

Re: Cannot Ping Without Source

Federico Coto Fajardo — Tue, 25 May 2010 13:45:27 GMT

If sending a PING to 10.10.30.x from the router, the router chooses to source its PING from 10.1.25.251 is because the routing
table points out that to reach 10.10.30.x is should use the 10.1.25.x interface.

You say that there's a route for 10.10.30.x pointing out via 10.10.10.1, but it does not seem to be working then...
What kind of router is this?
I saw the static routes that you post, but can you check the routing table to make sure that the router knows that to reach
10.10.30.x it should get out 10.10.10.5 instead than 10.1.25.251?

Federico.

Re: Cannot Ping Without Source

jtmullis82 — Tue, 25 May 2010 15:16:50 GMT

the router is a Alcatel Lucent 7705 SAR. The route table shows that 10.10.30.0/24 goes to 10.10.10.1. I believe the issue is the ASA, I need to specify where to route the 10.10.30.0/24 traffic.

Re: Cannot Ping Without Source

Federico Coto Fajardo — Tue, 25 May 2010 15:21:54 GMT

Joseph,

The issue is not the ASA.

The ASA is routing to the deafult gateway to get to both remote networks.

If you specify the source on the router, then it gets routed correctly on the ASA.

Federico.

Re: Cannot Ping Without Source

Federico Coto Fajardo — Tue, 25 May 2010 15:51:40 GMT

Joseph,

Could you test initiating the traffic from the remote site?

Federico.

Re: Cannot Ping Without Source

jtmullis82 — Tue, 25 May 2010 16:17:19 GMT

i added some more ACL's to allow 10.1.25.0/24 to 10.10.30.0 and the opposite on the remote end ASA and now the link works.

thank you for your help with this matter