Strange Cache Issue after Migration

[quickjeff]

Hi Guys, 

I wanted to reach to everyone in the community to see if someone has come across this issue. 

We have a client that had a website built in PHP. 

We provided our client with a new website built on ProcessWire.

Our client has their domain name registered  with register.com and their old website was built by another developer who was hosting the website in a virtual server at gandi.net.  

The DNS settings were as follows:

Domain name was pointed to the gandi.net in order to display the website files. 

The MX records were pointed to Google servers for company emails. 

The Name servers were as is which is the stock register.com name servers.

We were not able to speak with the old developer to setup a time to update the files so we were asked by our client to move forward without contacting the old developer.

How we setup the new website:

In order to avoid down time of the email accounts and not having to setup new MX records on another host, we simply setup our clients new website on GoDaddy shared hosting and changed the A record in their register.com DNS settings to point to the new hosting account. Basically, an IP change. Everything else they had stayed the same, meaning we did not change the MX records and we did not change the name servers.

Here is the issue:

Some website visitors are seeing the new website, some are seeing the old website.  We first thought it was due to browser caching or the propagation did not fully complete when they tried to visit the website.  After telling our client to wait until the new DNS settings or try to clear their cache, we thought they were all good to go. 

Now our client is contacting us saying that the issue is still happening. So we contacted register.com and had them resubmit the new DNS settings again, basically the same IP change we did.  

Result:

Some users are still seeing the old website on certain routers. We are also seeing the old website on certain routers we use and the new site on other routers. 

Can anyone provide some guidance? Has anyone seen this issue before?

We even pinged the website and it shows the correct server, we also used whatsmydns.net to see what the site is coming up as across the world and we also see the correct server. Lastly, we sent the url to our partners in Germany and they see the new website and not the old one. 

This is honestly the oddest issue I have seen and unsure as to why this is going on?

Here is our clients site:

medstarlab.com

[cstevensjr]

The only thing I would recommend is to flush the DNS cache for that domain.

[quickjeff]

@cstevensjr - I have flushed my system DNS cache, cleared my browser history etc. I am beginning to think that this is an ISP issue. 

Its very odd, I can see the new website when I connect to a hot spot, I can see the old site when I connect to my home office internet. 

[arjen]

Dns is strange. I've seen this before. In the end (after a week) it was solved, but I have no clue why it took so long.

1. When did you change the A record for the first time?

2. When did you change it for the second time? 

3. I've noticed that both www and non-www are loaded separately. Perhaps the www subdomain was changed later on? You can change the .htaccess so traffic is directed to either www or non-www.

I always use http://dns.squish.net/ to determine if the DNS is setup correctly ( medstarlab.com resolves to 192.186.217.98).

[cstevensjr]

Sorry, I wasn't very detailed.  

i actually meant you or the hosting provider (ISP) needs to flush the DNS cache from the cPanel (or it's equivalent).  On some hosting providers, you can do it yourself (i.e. DreamHost).  Normal DNS propagation takes at least 72 hours or longer.  It all depends on where the actual server is located, that's why some see the website where it's been moved to and others still see the old DNS information.  There are times where due to traffic congestion or other router issues, the updated information doesn't make it everywhere (across the world) in a timely manner.

Flushing the DNS cache will restart the process and usually things will start working as required.  You are correct that you need to work with the hosting provider (ISP) to clear this up.  GoDaddy support should have been on top of this, since they are hosting the website now.  Please open a trouble ticket with them and good luck.

[quickjeff]

@arjen

1.) The first time it was changed was 3 weeks ago.

2.) The second time it was changed 4 days ago.

3.) Correct, it was changed after. I can adjust the htacess. 

In regards to the DNS, medstarlab.com should resolve to 192.186.217.98 which is where its hosted now but sometimes I will see the old website (Only when I connect to the internet on my home router, which is Comcast Xfinity Internet.) I can see the new site when I connect to something else for data.

@cstevenjr

In regards to flushing the DNS, GoDaddy can see the new website, Register.com which is where the domain name is can also see the new website, when we ping the website url, we get the right IP for the right server. 

[cstevensjr]

@cstevenjr

In regards to flushing the DNS, GoDaddy can see the new website, Register.com which is where the domain name is can also see the new website, when we ping the website url, we get the right IP for the right server. 

Of course GoDaddy can see the website (it's local to them, they pushed or received the DNS change, they have multiple high capacity links and the affected website is at one of their facilities).  Of course register.com can see the website (they pushed or received the DNS change and have multiple high capacity links).

Other people (your users throughout the world) won't see the new website until the probable DNS propagation issue is resolved.  That's the most likely situation for this issue, however it's still most likely a hosting provider (ISP) problem and there could be other configuration issues.

The propagation of DNS information could be affected by many reasons (for the users who cannot see the new website).

[quickjeff]

@cstevenjr - Can you screen shot what you see?

[cstevensjr]

From Southern California (via Time Warner Internet link)

From Southern California (via AT&T Internet Link)

As an aside, hopefully your customers aren't getting your website confused with this one

which is medstarlabs.com versus medstarlab.com

Best Regards,

Charles

[quickjeff]

@cstevensjr - Thanks for the screen shot. 

This really boggles my mind.

I havent seen something like this, we might resort to finally pointing the Nameservers to our hosting and setting up their MX records. 

[quickjeff]

All, think we figured it out. 

There was one iPv6 Setting pointing to the old domain. We deleted this record, now we see the new site all the time. 

Its good to have an extra set of eyes on something, thanks to all that helped on this. 

[arjen]

Glad to hear you sorted it out. Dns can be frustrating at times.

[quickjeff]

@arjen 

Yes indeed. We are still waiting for it to fully propagate , can you screen shot what you see?

[Christophe]

I'm seeing the new website.

[quickjeff]

@Christophe, thanks for the update! Seems like the solution is working. I don't wan to Jinx it haha. 

I will report back the status after today.

[arjen]

I'm seeing the new one too.

[horst]

I'm seeing the new one too.

also here!