topic Re: Strange VPN Remote Issue in Network Security

Strange VPN Remote Issue

ciscosom — Mon, 11 Mar 2019 15:30:18 GMT

we have configured IPSEC Remote VPN on ASA 5510. Remote client is able to successfully authenticate and establish a tunnel , however user will not be able to ping any inside Hosts . As troubleshooting measure , i did enable ICMp trace 255 , i see the VPN Client ICMP request and a echo reply back from the Inside host hitting the Inside Interface of the Firewall . Can you please go through the configuration and let me know if anything needs to be changed .

Path the User will take is

VPn Usr-->Firewall ( inside ip 10.10.10.2)->L3switch (10.10.10.1)->Host (10.10.10.5)

Re: Strange VPN Remote Issue

ciscosom — Mon, 11 May 2009 18:35:52 GMT

Missed the attachment last time

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 18:58:19 GMT

Does anything else seem to work other than icmp?

Try:

same-security-traffic permit intra-interface

HTH,

John

Re: Strange VPN Remote Issue

ciscosom — Mon, 11 May 2009 19:05:55 GMT

Thanks for responding back John , modified the Configuration as per your suggestion , but no LUCK . No Traffic is being received back by the Remote client . Looks like the Return/response packet sent by the Inside host to the remote client is reaching the ASA but is not entering the IPSEC tunnel ..

Debug ICMp Trace output

echo reply from inside:10.10.11.1 to outside:192.168.14.1 ID=1 seq=758 len2

ICMP echo request from outside:192.168.14.1 to inside:10.10.11.1 ID=1 seq=759 l2

ICMP echo reply from inside:10.10.11.1 to outside:192.168.14.1 ID=1 seq=759 len2

ICMP echo request from outside:192.168.14.1 to inside:10.10.11.1 ID=1 seq=760 l2

ICMP echo reply from inside:10.10.11.1 to outside:192.168.14.1 ID=1 seq=760 len2

ICMP echo request from outside:192.168.14.1 to inside:10.10.11.1 ID=1 seq=761 l2

ICMP echo reply from inside:10.10.11.1 to outside:192.168.14.1 ID=1 seq=761 len

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 19:18:10 GMT

Are you trying to ping from 192.168.14.0 or are you trying to ping TO 192.168.14.0? Try adding "inspect icmp" to your default policy.

HTH,

John

Re: Strange VPN Remote Issue

ciscosom — Mon, 11 May 2009 19:23:36 GMT

Hi John ,

192.168.14.1 is the remote Client Ip assigned by ASA Ip pool .10.10.10.1 is the L3 Switch interface behind the Firewall .

I am trying to ping from 192.168.14.1 (remote vpn Client) ---> 10.10.10.1 (L3 Switch ).

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 19:34:32 GMT

Can you ping the .14.1 address from the ASA?

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 19:38:54 GMT

Do you have a route in your L3 switch back to the 192.168.14.0 subnet?

Re: Strange VPN Remote Issue

ciscosom — Mon, 11 May 2009 19:46:46 GMT

Hi John ,

Yes L3 has a defualt route pointing to ASA .

I think If routing was an issue we would not received the reply packets back from the host when we did the Debug ICMP Trace on the ASA , Your thoughts on this ?

Also i am not able to Ping the Remote Client (192.168.14.1) from the ASA

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 19:52:44 GMT

You should at least be able to hit it from the ASA. What do you get back if you do a:

sh vpn-sessiondb remote

Re: Strange VPN Remote Issue

ciscosom — Mon, 11 May 2009 20:03:01 GMT

First of all , i have no words to Thank you !!

You are correct ,Ideally we should be able to ping the Remote Client from the ASA Atleast . I think that 10.10.0.0 is not going into the ipsec tunnel when the destination iip is 192.168.14.0 for some reason ..Anywasy , below is the remote Db Output

Session Type: IPsec

Username : Administrator Index : 2

Assigned IP : 192.168.14.1 Public IP : X.X.12.200

Protocol : IKE IPsec

License : IPsec

Encryption : 3DES Hashing : SHA1

Bytes Tx : 1828 Bytes Rx : 8518

Group Policy : tom Tunnel Group : tom

Duration : 0h:00m:34s

NAC Result : Unknown

VLAN Mapping : N/A VLAN : none

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 20:06:28 GMT

Glad to help 🙂 What are they using to connect with? Cisco's VPN client? Is the stateful firewall on by chance?

And let me get this right, you've always tried to ping from this side to the 192.168.14.0 side, or have you tried 192.168.14.1 -> 10.x.x.x?

Re: Strange VPN Remote Issue

ciscosom — Mon, 11 May 2009 20:11:17 GMT

yes i have tried both directions ..

192.168.14.0 (remote client) ---> 10.x.x.x (host behind firewall_

10.x.x.x (host behind firewall)--> Remote client . No Traffic at all .

Yes , Remote USers connect using Cisco VPN Client 5.03XX version

No , Stateful firewall is OFF .

Re: Strange VPN Remote Issue

John Blakley — Mon, 11 May 2009 20:23:05 GMT

Do you get an entry in your routing table for that host? What shows as it's next hop?

Try this:

access-list VPN permit host 0.0.0.0

group-policy tom attrib

split-tunnel-specified excludespecified

split-tunnel-network-list value VPN

John

Re: Strange VPN Remote Issue

ciscosom — Tue, 12 May 2009 01:27:10 GMT

I tried that too , but no Luck . So i went ahead and opened a Case with TAC ,I will keep you posted on it ..But again thanks a ton for helping me on this issue , if you ever visit Atlanta ,Beer is on me .

Re: Strange VPN Remote Issue

nomair_83 — Tue, 12 May 2009 19:22:50 GMT

Can u try specific networks rather then using "any" in your nat0 acl?

Re: Strange VPN Remote Issue

ciscosom — Wed, 13 May 2009 00:10:59 GMT

Thanks for taking time to go through my Issue nomair . I modified the ip's but that did not make any differance