Topic: Very slow DNS response

[nicksin]

Hi All.

I seem to have picked up a funny. Not too sure if its a bug or possibly a config issue so Ill post here first.

I have a SME server version 7 rc 2. It sits in a DMZ as a mail and DNS Server.
Im getting a very delayed response from the server when it needs to resolve a name that doesnt seem to be cahced.
 For example doing a dig for yahoo times out 1st time and 2nd time goes through immediately.

Querying a remote dns server responds very fast. I had a look at the line  utilization and it is not related to congestion etc.

Any ideas / help will be greatly appreciated.

Thanks and Regards
Nic

 dig @10.10.9.5 www.yahoo.com

; <<>> DiG 9.3.1 <<>> @10.10.9.5 www.yahoo.com
; (1 server found)
;; global options:  printcmd
;; connection timed out; no servers could be reached

dig @10.10.9.5 www.yahoo.com

; <<>> DiG 9.3.1 <<>> @10.10.9.5 www.yahoo.com
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32366
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;www.yahoo.com.                 IN      A

;; ANSWER SECTION:
www.yahoo.com.          257     IN      CNAME   www.yahoo.akadns.net.
www.yahoo.akadns.net.   36      IN      A       209.73.186.238

;; Query time: 0 msec
;; SERVER: 10.10.9.5#53(10.10.9.5)
;; WHEN: Wed Jun 28 09:31:36 2006
;; MSG SIZE  rcvd: 81

[compsos]

We have been seeing something similar with 2 way satellite and thought it might be external. But your post sounds similar.
The client machines time out trying to get webpages but do get the page on the refresh.
Have you found any solutions?

[nicksin]

Nothing as yet,

Been considering moving from rc 2 to rc 3, otherwise downgrading to 6.x might be an option.
What version are you using ?

Rgds
Nic

[compsos]

Nic
We are using 7rc3. Have also noticed on yum updates timeouts and failures but think this is the satellite latency.
What tests did you do on your system I will try to duplicate.

[compsos]

Nic
I just stopped the dnscache and then tried a dig it failed restarted the cache and response was a lot better. Would need more extensive testing. Could it be a stale cache?

[chris burnat]

This sort of issues should really be  posted on the Bugtracker. (i) they can be investigated and resolved (i) they are on the records - posts in this forum tends to get lost after a while. Thanks on behalf the dev team.

[compsos]

We have not sent it to bugtracker as yet mainly because we need to confirm if it is SME or external. In our case the 2 way satellite has its own latency and weather problems that can affect performance.
Does anyone know a good test routine to isolate the point of delay for this type of issue?