DNS, Smoothwall/Internet Intermittent Fault

[IAMCloud_Curt]

Hi all,

 

Just posting here so I can possibly get someone to shed some light onto an issue I am currently receiving. We currently have 2 AD DNS servers installed here, it's been fine recently and no changes have been made on the DNS end. However we've hit a problem!

 

We currently have a 1GBps broadband package hosted from the local council and our ISP is JISC (Janet), in terms of speed it's not an issue, although our web pages are taking AGES to load, running a speed test we are getting 700mbps down, over 800 upload on an average test, but sometimes in the day if I randomly do a speed test, it might drop to about 20-40down..

 

But after doing some investigation of my own, I down thing it's a broadband issue, I think this is pointing to more a DNS issue, and it can't resolve the websites in a timely fashion. I've done basic nslookups to google, bbc, yahoo using our DNS servers and I don't get anything back, I receive the message;

 

"DNS request timed out. timeout was 2 seconds."

 

If I nslookup google.com using google DNS servers (8.8.8.8 or 8.8.4.4) I get hits to the website;

nslookup google.com 8.8.8.8

Server: google-public-dns-a.google.com

Address: 8.8.8.8

 

 

Non-authoritative answer:

DNS request timed out.

timeout was 2 seconds.

Name: google.com

Address: 216.58.208.174

 

nslookup google.com 8.8.4.4

Server: google-public-dns-b.google.com

Address: 8.8.4.4

 

 

Non-authoritative answer:

Name: google.com

Addresses: 2a00:1450:4009:811::200e

216.58.198.110

 

 

I've added 8.8.8.8 and 8.8.4.4 onto the DNS forwarders inside my smoothwall and it made no difference, I've cleared the cache on both DNS servers and restarted the services, also flushed dns.

 

I ran a functionality test on Smoothwall (built in network testing tool) and here were the results which I thought were quite alarming..

 

(attached the screenshot)

 

 

Both the council and smoothwall are now investigating this problem as to what it could be, I did update Smoothwall recently but nobody else seems to have experienced any problems like this since the update. The council got me to setup up a laptop in our server room that goes directly to there HP 5800 switch which then bypasses Smoothwall, and the internet is spot on when you bypass Smoothwall.

 

Any help is much appreciated as always.

 

Thanks,

 

Curt

Edited March 23, 2016 by IAMCloud_Curt

[rama1712]

We had the same issue when we moved to a new bb provider ours turn out to be the winhttp settings clients.

 

But we also found out that the DNS forwarders need to be on the AD DNS and not the SMoothwall and that fixed it for us within 20mins

 

Stuart