Parts of Account blocked "sometimes" (IP or DNS issue?)

[harionito]

Alright I got this weird issue with one of my dedicated servers.

I got a nameserver setup (always accessable), I also got 5 domains on that server.
But "sometimes" (3/4ths of the times I visit) the domain, I can only access the "postinfo.html" file, but none other (esp not the index.php), there isn't even a header sent back from these sites.

Whenever this happens, I restart the server, but it still doesn't make a difference.
but then again the next day I am somehow able to visit the page. (without changing anything).

My biggest problem is, I can't point down the problem ( I thought about perma IP bans ? btu only for single files?? ).

Anyways, appreciate any help, ask any questions if you need more information (I'm sure you do).

 

[Infopro]

If you're sure the domain name and nameservers are working correctly (you can check here http://www.intodns.com/ ) have you checked your server logs to see if you get any clues from them?

 

[harionito]

forgot to mention: whenever I check the site(s) with checkdns.net or intodns, everythings working just fine (esp the response headers etc. which I don't get from my IP :-? ).
and no clues in the server logs.

 

[JPC-Stefan]

Have you checked from any proxy server like atunnel.com when a page is unaccessible.

 

[harionito]

yes i did, same there, no header gets sent.
uh wait, right now i cant access the page again so i decided to check with intodns this time (only checked with checkdns before which gives me 100% positive results).
so it pretty much tells me:
ERROR: Some of your DNS servers do not have A records at all. I could not find any A records for the following DNS servers:
ERROR: One or more of your nameservers did not respond:
(and some other stuff).
weird.

SOOOO I went in and added A records (which weren't there for some reason? must have deleted them while experimenting wiht vhost.).

Anyways, now I get different errors from intodns.com:
WARNING: Not all of your nameservers are in different subnets
WARNING: Single point of failure
Your SOA EXPIRE number is NOT OK

 

[Infopro]

The first error would stop your site from working, the rest, probably not.