DNS problems?

[SaintAelphaba]

I've spent the whole day googling this but can't get anywhere with it at all so I think it's time to ask for help! I'm way out of my depth and don't know what I'm looking for so apologies if this post is garbled and has too much/too little information.

 

First of all, I'm in Madagascar so don't have great internet connection at the best of times. I'm in a small office and we usually have 3 networks (all from the same provider) but currently only 2 are working as one router is broken, so we're overloading them and things are slower than normal.

 

Basically, some websites just don't load. On a Mac in Safari there are no error messages, just a page that never loads. On a PC in IE or Firefox you get a general error message, but Chrome says it's a DNS problem. I think this has been a problem since I arrived here 6 months ago as I've always had some websites that don't work in the office but will work at a local hotel, but it seems to be getting worse over the last couple of weeks.

 

Copied from an email I sent earlier:

 

So, Chrome helpfully tells me that the problem is because DNS lookup failed. It suggests:

• restarting the router (tried this - has no effect);
  
• checking the DNS settings (which I can do on individual computers but I don’t know what I’m looking for);
  
• changing a setting about predicting network actions which was the first thing I tried but that doesn’t work;
  
• checking Chrome is permitted by the firewall (clearly not the problem as it’s the same across all browsers/computers)
  
• checking proxy server settings if we’re using one – I don’t know what this means or whether we use one!
  

Taking two websites as examples: trip advisor and Kenya Airways.

trip advisor:

On my Mac using Safari: will not load if the address is typed into the bar. Also will not load through Google.

On PC using IE/Firefox/Chrome: as above.

 

Kenya Airways:

Mac: will not load through Google but will load if the address is typed in on my mac, but not on others.

PC: will not load either way.

 

I've been looking at websites and forums all day but can only find things about this happening on one computer and therefore changing that computer's settings. However, this is happening on everyone's computers, Mac and PC, old, new and somewhere in between, all browsers and both our networks.

 

I literally have no idea what to do about this and there's no one here who can help since we lost our tech support guy a couple of months ago. It's making it really difficult to work as more and more websites are affected and obviously we rely a lot on the net for communication.

 

Any ideas much appreciated (I'm not very tech-literate but can follow instructions and have a basic idea about most things...) as I'd really like to get this sorted. I don't feel like I've explained the problem very well so will obviously answer any questions as best I can.

 

Many thanks.

[BeeCeeBee]

First of all, I'm in Madagascar so don't have great internet connection at the best of times. I'm in a small office and we usually have 3 networks (all from the same provider) but currently only 2 are working as one router is broken, so we're overloading them and things are slower than normal.

 

This is where you lost me a bit. This is an office, correct? Are you saying that you have 3 different incoming lines from an internet service provider (ISP) or do you have a server somewhere. If one router is broken, are the other computers that were not on the broken server working properly?

 

It may be very difficult for anyone to provide much advice without a good deal more information about your configuration.

 

But do not lose hope, there are many people here who may have a far greater understanding than me.

[SaintAelphaba]

Sorry, my understanding isn't really good enough for even explaining the problem!

 

We don't have a server. There are 3 different routers, so I'm guessing 3 different incoming lines... and on any computer you can pick which network you connect to, so the people who were using the one which is now broken are all using a different one.

 

Does that help...?

 

If more information is needed I can always email our tech support guy who left and I think he'd be able to provide the info or tell me how to find it.

[BeeCeeBee]

If more information is needed I can always email our tech support guy who left and I think he'd be able to provide the info or tell me how to find it.

I think that would be a good idea. The three networks apparently relate to the different servers but not necessarily to different incoming service. Are your problems related to wireless networking or are all these computers hard wired?

[SaintAelphaba]

It's all wireless.

 

My brain is completely fried right now but I'll attack the problem again when I'm in the office tomorrow afternoon. Thanks for the replies so far.

[Synapse]

Not wanting to be negative, but I'd be surprised if we could sort this out on a forum.

 

Your ex IT guy may have set the DNS manually per machine, or he may not. The 3 routers may have different DNS servers set up, they may not, if they are there may be an agreement between your IT guy and the ISP.

 

Also, there may be a fault elsewhere.

 

Are you able to log in to the routers, including the faulty one?

[BeeCeeBee]

Just a quick note, my post no 4 above makes reference to different "servers" when I meant to say "routers." Otherwise I am afraid that I have to agree with synapse by the time you get someone who knows how it is set up to explain it to us, he may as well just fix it.

[KenB]

Hi and welcome to ExTS

 

I have to agree with the others - there are too many variables here.

 

Try this on the computers that cannot access Kenya Airways:

Open the browser and highlight the address bar ( http:// etc etc ) > Delete it

Type in ( or copy and paste this ) 217.64.230.153 then hit ENTER

 

This is the IP Address of Kenya Airways

 

Can you access it this way ?

[SaintAelphaba]

Thanks for all the help so far. I appreciate it's not easy as I can't give you the information you need!

 

I tried the Kenya Airways website using the IP address and it worked. What does that mean?

 

I'll email our old guy this morning and hope he can pass on some useful information but he's in America so I probably won't get anywhere til after the weekend given the time differences.

 

Many thanks everyone.

[KenB]

I think it is a DNS problem.

 

What is the make and model number of the routers ?

 

Is the problem with ALL machines on the network ?

 

==============

 

On a machine that cannot connect to Kenya Airways normally:

 

Start > Computer > C:\ > Windows > System32 > Drivers > etc

Double click on "Hosts"

When prompted select "Notepad"

Copy the Hosts file and post here please.

 

Do not alter it in any way.

Do not save it.

 

==============

 

Right click on the "Hosts" file > Properties

Is "Read Only" checked ?

If not put a check there > OK

[SaintAelphaba]

# Copyright © 1993-2009 Microsoft Corp.

#

# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.

#

# This file contains the mappings of IP addresses to host names. Each

# entry should be kept on an individual line. The IP address should

# be placed in the first column followed by the corresponding host name.

# The IP address and the host name should be separated by at least one

# space.

#

# Additionally, comments (such as these) may be inserted on individual

# lines or following the machine name denoted by a '#' symbol.

#

# For example:

#

# 102.54.94.97 rhino.acme.com # source server

# 38.25.63.10 x.acme.com # x client host

 

# localhost name resolution is handled within DNS itself.

# 127.0.0.1 localhost

# ::1 localhost

 

The read only box wasn't checked so I changed it - the above copy and paste is from before I did that though, does that make a difference?

 

One router is Netgear N600 WNDR3400. The other is ZyXEL P-334U. The problem is with all machines on both networks that we use.

[KenB]

does that make a difference?

No

 

Sometimes malware can add to the Hosts file.

 

# 127.0.0.1 localhost

# ::1 localhost

 

Try this ............. It will probably mess things up and you will need to change it back.

Mine is set as below:

 

127.0.0.1 localhost

::1 localhost

 

I assume that the OS on this machine is Win7 ( this is a win7 hosts file set up )

With the # the line is remmed out.

 

Not sure how your tech set up the system but it is easy to test.

 

Go back to the "Hosts" file and remove the "Read Only" > OK

 

Open the file in Notepad and remove the # from the 2 local host lines.

 

File > Save in Notepad.

Close Notepad and open Hosts file again to make sure the changes have taken place.

 

If all is OK right click on Hosts > Properties and check "Read Only" again.

 

Try Kenya Airways etc.

 

Checking the read only option will not allow the Hosts file to be added to - unless you uncheck it.

 

 

Which OS are you using on this machine ?

[SaintAelphaba]

Hit a wall, I'm afraid. I can't save the file because I don't have permission and have to contact an administrator. I guess this is to do with the network and I don't have admin info (waiting on a response from our old techie). It will only let me save in My Documents which I think isn't right...?

 

Tried on a couple of Windows 7 machines. We also have Linux and various Mac OSs if it would be easier/make a difference to do it off any of these.

 

Thanks so much for your help.

[KenB]

If it is a Win 7 machine then the Hosts File is correct.

I was half hoping that it may have been another OS.

 

Not sure this is totally correct path for Win7 but try it ( I am on Vista )

 

Start > Control Panel > Nework & Sharing > Manage Network Connections

Right click on "Wireless Network Connections" > Properties

Highlight TCP/IPv4 > Properties

 

Are both IP Address and DNS set to "Obtain Automatically" ?

 

============

 

It looks as if this is a router or ISP problem if all of these machines and OSs are affected.

 

Trying a work-around for one machine if we can.

[SaintAelphaba]

Since it affects both routers I guess it's more likely to be an ISP problem then, unless both routers were set up wrong...?

 

Ugh. I don't think Telma will fix this, they're useless!

 

OK, I've got "Network and Internet" and then don't have a "Manage Network Connections" option and can't find anything that leads me to that info. The closest I can get is the "Network Connection Details" for the network I'm currently connected to but doesn't have the info you mention.

 

Actually, found it. Both are already set to "obtain automatically".

[KenB]

OK

 

Go back and Put a check in " Use the following DNS ...."

In the preferred type in 8.8.8.8

In the one below type in 8.8.4.4

OK this.

 

Try the connection again.

 

If no go - change it back to automatic.

[SaintAelphaba]

I got so excited, it worked for the Kenya Airways website! But I think maybe it had just remembered the IP from when I typed it in earlier, as it didn't work for other sites.

 

Just chatting to the ex-techie and he thinks he might be able to log in remotely to check the settings, as long as Telma haven't reset the routers (which they probably have). He can't do it at work so will have to wait until after the weekend!

 

Thanks for all the help, no doubt I will be back here next week!

[KenB]

Let us know how you get on.

If your ex tech resolves the problem I would be interested to know what it was :)

[SaintAelphaba]

So, I logged into the router of the one network which is actually working today and played with the DNS settings. Google's don't work. I gave techie the servers which were already there and he got a response from both of them but said sometimes the connection would just time out and wasn't very reliable.

 

So... who knows. Need to contact ISP.

 

I just learned how to do a trace route thingy, that was exciting and told me nothing!

[KenB]

Keep us informed - :)