FAILURE SYSTEM FOR DOMAIN NAME SYSTEM CLIENT

• US 20110202793A1
• Filed: 02/12/2010
• Published: 08/18/2011
• Est. Priority Date: 02/12/2010
• Status: Active Grant

• Current Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Original Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Inventors: Xu, Ce
• Granted Patent: US 8,103,915 B2
• Time in Patent Office: Days
• US Class Current: 714/15
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/58 Caching of addresses or names
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A method performed by a domain name service client includes storing DNS entries in a local cache; sending a DNS query to another device to obtain an update to one of the DNS entries; determining whether a DNS response is received; and resetting a time-to-live (TTL) timer associated with the one of the DNS entries when the DNS response is not received.

Claims

1. A method comprising:

storing, by a domain name system (DNS) client device, DNS entries in a local cache;

sending, by the DNS client device, a DNS query to another device to obtain an update to one of the DNS entries;

receiving a DNS response;

inspecting a response code value included in the DNS response; and

determining whether the response code value corresponds to an error category that indicates that the one of the DNS entries is to be deleted, or that the one of the DNS entries is to be saved and a time-to-live (TTL) timer is to be reset.

2. The method of claim 1, wherein when inspecting, the method further comprises:

determining whether a DNS resource record (RR) included in the DNS response is empty or not; and

inspecting the response code value from the DNS response when the DNS RR is empty.

3. The method of claim 1, wherein when determining whether the response code value corresponds to the error category, the method further comprises:

determining whether the response code value corresponds to a temporary failure or a permanent failure.

4. The method of claim 3, further comprising:

resetting the TTL timer associated with the one of the DNS entries when the response code value corresponds to the temporary failure.

5. The method of claim 3, further comprising:

deleting the one of the DNS entries from the local cache when the response code value corresponds to the permanent failure.

6. The method of claim 1, wherein when the DNS response is received, the method further comprises:

determining whether a DNS resource record (RR) included in the DNS response is empty or not;

updating the one of the DNS entries when the DNS RR is not empty; and

resetting the TTL timer associated with the one of the DNS entries.

7. The method of claim 1, further comprising:

storing data that maps response code values to error categories; and

wherein when the DNS response is received and the DNS response includes an empty DNS resource record, the method further comprises;

determining the error category associated with the response code included in the DNS response based on the data stored.

8. The method of claim 7, further comprising:

comparing the response code included in the DNS response with the data stored.

9. A device comprising:

a domain name system (DNS) client;

one or more memories to store instructions; and

one or more processors to execute the instructions in the one or more memories to;

store DNS entries in a cache, wherein the DNS entries provide DNS resolutions;

send a DNS query to another device to obtain an update to one of the DNS entries;

receive a DNS response;

inspect a response code value included in the DNS response; and

determine whether the response code value corresponds to an error category that indicates that the one of the DNS entries is to be deleted, or that the one of the DNS entries is to be saved and a time-to-live (TTL) timer is to be reset.

10. The device of claim 9, wherein the device comprises one of a network device or an end device.

11. The device of claim 9, wherein when inspecting, the one or more processors are to execute instructions to:

determine whether a DNS resource record (RR) is empty or not when the DNS response is received; and

inspect a response code value from the DNS response when the DNS RR is empty.

12. The device of claim 11, wherein when determining whether the response code value corresponds to the error category, the one or more processors are to execute instructions to:

determine whether the response code value corresponds to a temporary failure or a permanent failure.

13. The device of claim 9, wherein the one or more processors are to execute instructions to:

delete the one of the DNS entries when the response code value corresponds to the error category that indicates that the one of the DNS entries is to be deleted.

14. The device of claim 9, wherein the one or more processors are to execute instructions to:

continue to save the one of the DNS entries when the response code value corresponds to the error category that indicates that the one of the DNS entries is to be saved; and

reset the TTL timer associated with the one of the DNS entries.

15. The device of claim 9, wherein the one or more processors are to execute instructions to:

determine whether a DNS resource record (RR) is empty or not when the DNS response is received;

update the one of the DNS entries with the DNS RR when the DNS RR is not empty; and

reset the TTL timer associated with the one of the DNS entries.

16. The device of claim 9, wherein the one or more processors are to execute instructions to:

reset the TTL timer associated with the one of the DNS entries when a DNS response is not received.

17. A tangible computer-readable medium containing instructions executable by at least one processor, the computer-readable medium storing instructions to:

manage domain name system (DNS) entries in a cache associated with a DNS client;

send a DNS query to another device to obtain an update to one of the DNS entries;

receive a DNS response;

inspect a response code value included in the DNS response; and

determine whether the response code value corresponds to an error category that indicates that the one of the DNS entries is to be deleted, or that the one of the DNS entries is to be saved and a time-to-live (TTL) timer is to be reset.

18. The tangible computer-readable medium of claim 17, wherein the instructions to inspect further comprise one or more instructions to:

determine whether a DNS resource record (RR) is empty or not when the DNS response is received; and

inspect the response code value from the DNS response when the DNS RR is empty.

19. The tangible computer-readable medium of claim 17, further comprising one or more instructions to:

continue to save the one of the DNS entries when the response code value corresponds to the error category that indicates that the one of the DNS entries is to be saved; and

reset the TTL timer associated with the one of the DNS entries.

20. The tangible computer-readable medium of claim 17, further comprising one or more instructions to:

delete the one of the DNS entries when the response code value corresponds to the error category that indicates that the one of the DNS entries is to be deleted.