08-14-2013 06:34 PM - edited 03-11-2019 07:25 PM
Hi Everyone,
On my ASA i do not have the config
dhcpd dns 64.59.144.19
this is my ISP DNS.
Without the command i am still able to access the internet and ASA log shows
Aug 14 2013 19:31:09: %ASA-6-302016: Teardown UDP connection 1481 for outside:64.59.144.19/53 to DMZ:192.168.70.2/60527 duration 0:00:00 bytes 90
Aug 14 2013 19:31:09: %ASA-6-302016: Teardown UDP connection 1480 for outside:64.59.144.19/53 to DMZ:192.168.70.2/53809 duration 0:00:00 bytes 390
Is this default behaviour?
Regards
MAhesh
Message was edited by: mahesh parmar
Solved! Go to Solution.
08-14-2013 08:47 PM
Hello,
If you do not have provided to them the DNS server via DHCP how are they using the protocol?
They might have it statically configured or other device is providing that service, do a capture on the client side with wireshark and check where they get the DNS address from.?
Can you doble check that,
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
08-14-2013 08:51 PM
Hi Mahesh,
Are you perhaps using DHCP also on the ASAs "outside" interface?
Do you have this configured perhaps?
dhcpd auto_config outside
You can view this with command
show run dhcpd
- Jouni
08-14-2013 10:20 PM
Hello,
I mean the switch is aware of the DNS servers but based on the configuration you provided there are no sufficient inputs to determine whether it's broadcasting the DNS IP addresses.
So on the client side or any other Active Directory setting there is no DNS configuration setting?
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
08-15-2013 06:16 PM
Hello Mahesh,
with the capture we will not be able to look for something useful as the client already has the DNS server.
What would be good is to check on the client side any configuration related to DNS on the LAN or WLAN properties.
We can see that they are using 64.59.144.19 as the DNS server but the question is how the get it, not from the ASA.... the Switch with only that configuration will not be the one...
There got to be some other clue that you could provide us
7 2.650999 192.168.70.3 64.59.144.19 DNS 73 Standard query A www.google.ca
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
08-14-2013 08:47 PM
Hello,
If you do not have provided to them the DNS server via DHCP how are they using the protocol?
They might have it statically configured or other device is providing that service, do a capture on the client side with wireshark and check where they get the DNS address from.?
Can you doble check that,
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
08-14-2013 08:51 PM
Hi Mahesh,
Are you perhaps using DHCP also on the ASAs "outside" interface?
Do you have this configured perhaps?
dhcpd auto_config outside
You can view this with command
show run dhcpd
- Jouni
08-14-2013 09:51 PM
Hi Jouni,
Here is info
ciscoasa# sh run dhcpd
dhcpd address 192.168.70.2-192.168.70.254 DMZ
dhcpd enable DMZ
!
dhcpd address 10.0.0.2-10.0.0.100 inside
dhcpd enable inside
Seems the switch connected to ASA is providing the DNS
3550SMIA# sh run | inc dns
dns-server 64.59.144.19
dns-server 64.59.144.19
dns-server 64.59.144.19
This switch is directly connected to ASA outside interface.
ASA outside interface has static ip.
interface Vlan1
description Connection to Outside 3550A
nameif outside
security-level 0
ip address 192.168.71.2 255.255.255.0
So in this scenario switch is provding the dns?
Regards
Mahesh
08-14-2013 10:20 PM
Hello,
I mean the switch is aware of the DNS servers but based on the configuration you provided there are no sufficient inputs to determine whether it's broadcasting the DNS IP addresses.
So on the client side or any other Active Directory setting there is no DNS configuration setting?
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
08-15-2013 05:52 PM
Hi Julio,
I have attached the wireshark capture under the original post.
now is cap file.
Can you have a your expert look
Regards
Mahesh
08-15-2013 06:16 PM
Hello Mahesh,
with the capture we will not be able to look for something useful as the client already has the DNS server.
What would be good is to check on the client side any configuration related to DNS on the LAN or WLAN properties.
We can see that they are using 64.59.144.19 as the DNS server but the question is how the get it, not from the ASA.... the Switch with only that configuration will not be the one...
There got to be some other clue that you could provide us
7 2.650999 192.168.70.3 64.59.144.19 DNS 73 Standard query A www.google.ca
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
08-15-2013 06:37 PM
Hi Julio,
You are the best i checked the TCP properties the DNS was hard coded there instead of obtain it automatically.
Best regards
MAhesh
08-15-2013 08:15 PM
Hello Mahesh,
Thanks for the kind words, I really appreciate them,
Glad to know that I could help,
Check my blog at http:laguiadelnetworking.com for further information.
Cheers,
Julio Carvajal Segura
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