DNS Expert

[Goz]

I'm after a recommendation for someone who can help us with a tricky little DNS issue.

Now, we host websites and we know a bit about DNS.

But, we've taken on a client who has two websites. He can be out on the road, use somebody's wifi and not be able to access his websites.... but, at the same time, he can access his websites using 3G on his mobile phone.

He'll be in other locations and have absolutely no problem in getting access using broadband there.

He has customers who ring to tell him his website is down.

We've done all our usual DNS checks and nothing comes up....

So, we're looking for a DNS expert who can take a look.

Any recommendations?


thanks

Andy

[malbro]

I'm after a recommendation for someone who can help us with a tricky little DNS issue.

Now, we host websites and we know a bit about DNS.

But, we've taken on a client who has two websites. He can be out on the road, use somebody's wifi and not be able to access his websites.... but, at the same time, he can access his websites using 3G on his mobile phone.

He'll be in other locations and have absolutely no problem in getting access using broadband there.

He has customers who ring to tell him his website is down.

We've done all our usual DNS checks and nothing comes up....

So, we're looking for a DNS expert who can take a look.

Any recommendations?


thanks

Andy

It is quite possible that the system he is using in certain places does not allow Internet Access to 'strange' computers, it all depends on how the router is setup.

Another possibility is that he has a fixed some or all the network setting on the laptop, in which case it will work only if the local area network recognises the laptop as being in the same logical network as itself and thus allow access. Setting the laptop to use automatic configuration will often solve this problem.

The 3G phone is probably a red herring as this can use its own access to the internet via the mobile network APN, instead of the WiFi connection.

My solution in cases where I am unable to access the iInternet from a 'strange' LAN, is to use my mobile phone and switch it to be an APN (most smartphones can do this). I then link the laptop to this new WiFi access point and voila I have Internet access although not as fast as I would like.

[Goz]

I can see what you're saying Malcolm... but he has customers who ring him up and tell him they can't see the website(s) either. Curious!!

[malbro]

I can see what you're saying Malcolm... but he has customers who ring him up and tell him they can't see the website(s) either. Curious!!

Where does he host the web sites

[Goz]

stratoserver in Germany .... although we plan to host them in the UK when this is resolved.

[fergusw]

Andy,
Connecting to a Wifi network AND being able to access the internet through that network are two separate things e.g. Airports are a good example where you can connect, buy only to the paywall.........something similar may be happening here.

It is rare for a DNS issue to cause intermittent problems, unless there is a direct issue with the parent nameserver records themselves i.e. 2 or more conflicting parent name server records.

Customers ringing him telling him website is down is a little more concerning. If DNS corruption is ruled out then I'd look to the routing and the hosting server i.e. check the stats and logs to see if there are any corroborating stats to show problems or outages at the time customers report.

External site checks are good for this too: e.g. http://www.downforeveryoneorjustme.com/
Handy for your client to have should a customer call - i.e. identify if it's a customer issue or not.

Could be an issue with routing through an ISP to the hosting area etc which maybe explain why some cannot see whilst others cannot. A traceroute performed from customer machine would help, although not many customers would know how to do that, nor would they want to do that either!

Doubtful it's DNS - most likely hosting based.......

[completerookie]

have you thought of over-ridding the dns server settings, and setting one to a "known working one" and the second to "another totally different known working one"
you don''t have to accept the dns servers they issue.

A work, the boss installed a mac tv, and it totally overtook all the dns server settings and ip ranges,
took a while to work out why we couldn't access anything.
once I over-rode the settings, I could get back out on the net and "see things again"

[malbro]

stratoserver in Germany .... although we plan to host them in the UK when this is resolved.

Unlikely to be the hosting setup, although I am not familiar with that provider.

Summarising
1/ Some customers have issues reaching the web site, this could be down to a specific ISP, are all the customers using the same ISP, do they always have problems or is it intermittent, are they all from one area ......


2/ The problems with the laptop could be related but may by something else entirely, do you have a record of where he was when the problems occurred, do they always happen at the same customers, which ISP do these customers use.

3/ Using the mobile to access the site may be a clue but we don't know if the mobile is using WiFi to the same broadband connection or if it is using the Mobile Network to gain access to the Internet, in which case it is not related at all.

You need a lot more information to narrow down the problem and I am not sure you will be able to get the information you need.

As Fergus says try a monitoring service to check availability of the web site so you can check this when customers complain.

[Goz]

Ah! The plot thickens (or thins?)

Found out from the client today that they've been having these problems..... for about as long as they hosted with stratoserver!

We're going to move the sites to a VPS in the UK.


Thanks for all your input guys - I'll be back if we're getting the same problems after the move!

[cbarling]

I'm come across this issue a couple of times over the years.

It's always turned out to be someone's routing table is misconfigured, somewhere deep in the bowels of the Internet.

You have to run a traceroute command (can't remember the exact format but it's a standard command from the windows command line) from the place that can't see your site and this will show where in the route the link is broken. You then need to speak to your provider and try to get them to tell the provider at fault what has gone wrong.

This happened last year with BT resulting in no-one on BT broadband being able to see any SellerDeck hosted sites (or ITV and numerous other big sites). They fixed it in a couple of hours.

Of course, your plan to simply bring the site into the UK is easier and probably quicker, but I thought you might be interested in the explanation.

Chris

[Goz]

Thanks Chris.