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Cisco ASA 8.4 denies packets between two internal subnets

Posted on 2011-09-23
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Last Modified: 2012-05-12
Hello. Our basic config..

10.10.1.1 - ASA 8.4 (5510)
10.10.1.3 - router to 10.10.15.0 subnet

asa has route..

route inside 10.10.15.0 255.255.255.0 10.10.1.3 1

asa can ping 10.10.15.x hosts, however we can't communicate with them, and get this error on the asa:

Deny inbound UDP from 10.10.1.21/5060 to 10.10.15.105/5060 on interface inside


Current config is almost out of the box.


I have tried creating access-lists and network object, but my knowledge is weak, so no success. If someone could please tell me which lines to add and break it down to me, I would very much appreciate it.

Should be a very basic question, no VLANs or anything.

Thanks
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Question by:arthurk123
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7 Comments
 
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Expert Comment

by:jmeggers
ID: 36591097
Looks like the host is sending to the ASA when it should be sending to the 10.10.15.105.  The ASA won't redirect, so my guess is that's why it's denying the packet.  Is the host (10.10.1.21) using the ASA as its default gateway?  Since the ASA won't redirect, I believe it should be using the router as its default gateway instead.
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Author Comment

by:arthurk123
ID: 36592820
Yes, the ASA is the default gateway, it is replacing our existing Peplink firewall

The router is just a point to point T1 connection to another office up the street

I am not trying to link different interfaces with different subnets, just stop the ASA from denying the above packets...


I refuse to believe the ASA won't do this. Even a 50 dollar Linksys has the option to put in static routes...
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Accepted Solution

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dcj21 earned 500 total points
ID: 36593615
Need to turn on same security traffic. That allows traffic with the same security level to cross the ASA including going in and out the same interface.

same-security-traffic permit {inter-interface | intra-interface}

inter-interface - Permits communication between different interfaces that have the same security level.
intra-interface - Permits communication in and out of the same

interface.http://www.cisco.com/en/US/docs/security/asa/asa72/command/reference/s1_72.html#wp1289167
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Author Comment

by:arthurk123
ID: 36593735
Thank you, you are GOD!

I did run a packet trace and got...

Phase: 1
Type: ROUTE-LOOKUP
Subtype: input
Result: ALLOW
Config:
Additional Information:
in   10.10.15.0      255.255.255.0   inside

Phase: 2
Type: ACCESS-LIST
Subtype:
Result: DROP
Config:
Implicit Rule
Additional Information:

Result:
input-interface: inside
input-status: up
input-line-status: up
output-interface: inside
output-status: up
output-line-status: up
Action: drop
Drop-reason: (acl-drop) Flow is denied by configured rule


I thought same security traffic was only for different interfaces talking to each other, not same interface.

Thank you many times!
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Author Closing Comment

by:arthurk123
ID: 36593744
Exact answer I needed
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LVL 4

Expert Comment

by:dcj21
ID: 36593745
This has bit me before - ;-)

Please mark my answer as helpful, I'm trying to earn points for my membership
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Author Comment

by:arthurk123
ID: 36593752
done!
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