Can't connect to forums with windows machines

[WTDdallas]

I have several windows 7 machines with chrome, firefox, safari and none of them can access these forums, just on this site, don't have problems with any other site.
Anything from forums.lazarus.freepascal.org/... times out every time. 

Checked fire wall, added site to safe list, no luck.

I have to use my Linux mint 17 machine to access forums?

Any Ideas??

[Martin_fr]

I am not sure. I vaguely recall  that there may be an issue with certain MTU, if fragmentation is not allowed. But I may be wrong.

If so, that may get solved in the next few weeks, as there will be some changes to the hosting.

[ausdigi]

I'm currently connected using Win10 via NAT and WinXP worked from within a virtual machine too.

[wildfire]

Win 10,  Win XP and Android tablet. No access issues here.

[WTDdallas]

Win 10,  Win XP and Android tablet. No access issues here.

All I have is windows 7 units    , and none of them working 

the Mint 17 is what i have to boot up to check forums 

[wildfire]

I'll setup a win 7 VM tomorrow but I doubt the OS is the issue, look at your settings (as said before specificully MTU) other than that your ISP.

[molly]

just shooting something into the dark rabbit hole: All the same OS, similar setups, all using the same adblocker/anti virus software ? Tampered with host-files ? Can you ping the forum servers ? How does google-translating the forums work for you (or using any other proxy for that matter) ?

[HeavyUser]

windows 7 here no problems accessing the forums.

[WTDdallas]

just shooting something into the dark rabbit hole: All the same OS, similar setups, all using the same adblocker/anti virus software ? Tampered with host-files ? Can you ping the forum servers ? How does google-translating the forums work for you (or using any other proxy for that matter) ?

Spybot,AVG free, no adblocker, Malwarebytes

I have not tampered with host-files.

I can ping forums ok, but can not access IP directly from browser, Times out too.

No Proxy, Time warner Cable ISP. works fine on mint device, android tables on same box.

MTU = 1500 windows.

Added site to safelist

I can access the rest of the site fine.  Just not the forum. I know strange. Is the forums on another server?

[engkin]

I can access the rest of the site fine.  Just not the forum. I know strange. Is the forums on another server?

Yes, it is. I can see two different IP numbers for forum.lazarus.freepascal.org and www.freepascal.org.

Assuming it is a fragmentation issue:
Make sure to activate "Do Not Fragment" when you ping the forums (using -f) and to specify the size of the buffer (start with your MTU - 28):

Code: DOS  [Select][+][-]

1. ping forum.lazarus.freepascal.org -f -l 1472

When it fails you should see something like:

Packet needs to be fragmented but DF set.

then just reduce the buffer size until it works.

On my side the ping works with a buffer size of 1412, meaning my MTU should be set to 1440 or less.

[WTDdallas]

Didn't help I dont think it is MTU, anything else?

[engkin]

Didn't help I dont think it is MTU, anything else?

Was not meant to help. It was how to find the MTU value that might work. Hoping you'll share it with us. When you find the proper MTU value, you still need to change Windows' MTU.

[ausdigi]

You mentioned IP addresses but didn't say what you get. Check that you get the same values from Windows & Linux hosts. I get the following:

Code: [Select]

Name:    forum.lazarus.freepascal.org
Address:  80.123.225.56You could also try to make HTTP connections (using telnet or similar) or write a program in Lazarus with a TCP component to connect to forum.lazarus.freepascal.org on port 80.

[WTDdallas]

I can access the rest of the site fine.  Just not the forum. I know strange. Is the forums on another server?

Yes, it is. I can see two different IP numbers for forum.lazarus.freepascal.org and www.freepascal.org.

Assuming it is a fragmentation issue:
Make sure to activate "Do Not Fragment" when you ping the forums (using -f) and to specify the size of the buffer (start with your MTU - 28):

Code: DOS  [Select][+][-]

1. ping forum.lazarus.freepascal.org -f -l 1472

When it fails you should see something like:

Packet needs to be fragmented but DF set.

then just reduce the buffer size until it works.

On my side the ping works with a buffer size of 1412, meaning my MTU should be set to 1440 or less.

1394 was the number that worked

[engkin]

1394 was the number that worked

Change your Windows MTU to 1394+28=1422:
Get an Elevated Command Prompt
Type the following command:

Code: Pascal  [Select][+][-]

1. netsh interface ipv4 set subinterface "Your Network Name Goes Here" mtu=1422 store=persistent

Use 1422 or less and put your network name "Local Area Connection" or whatever you have.