Website down

site down to one user but not to another

[MillieF]

Sorry to ask a basic question, but is it possible for a website to be down to one user (ie me) but for someone else to be able to see it (I phoned a friend to check it and he can view and interact with the site)? We are on different IPs and the rest of the web works fine for me, it's just that one site.

[Leosghost]

yes it's normal ..usually means that the one who cant see the site has a problem on DNS to that site resolving( maybe at their ISP's cache )..if it persists over 24 hours then check the sites nameservers status yourself ..

Meantime ..if you know another site hosted on the same server try to connect to it via the address bar ..if you cant then it's DNS ..and often temporary ..

I sometimes cant get to WebmasterWorld ..but can get elsewhere ..

Welcome to WebmasterWorld [webmasterworld.com] :)

[edited by: Leosghost at 2:31 pm (utc) on Aug. 20, 2009]

[MillieF]

Many thanks for your reply. What I don't quite understand is why I can access other sites and not this particular one. Do you mean it can be down to my ISP and not the missing site's ISP?

[Leosghost]

yes ...can be either ..( when I cant reach here because my ISP in France glitches ..WebmasterWorld is still "up" ..just i cant see it ) hence try to access another site on the same server ..

That is a horribly simplified idea of DNS ..that i just posted ..there are some threads here that go into all the gory details ..but i gotta run ..:)

[MillieF]

Thank you, and for the welcome :-)

[idfer]

This happened to me the other day: i lost web access to all the websites on my cheap hosting account, ftp and email still worked. It turns out i was fooling around with the password settings in a protected directory, that resulted in several unsuccessful login attempts and the host's firewall automatically blocked my IP. A quick email to support resolved the problem... You may be having a similar problem.

[rocknbil]

Do you mean it can be down to my ISP and not the missing site's ISP?

Not always. I've spent days over this particular issue with an administrator, and as it turns out my router was being weird. We connect via satellite, with the modem sharing the connection over a router.

The only consistent thing that fixes it for me it was rebooting the router and computers. It can run for weeks or days without a problem, when it goes wonky, reboot the comps, reboot the router, it's all fine again.

[dpd1]

Years ago we had a problem where I found that our company site was not accessible through Earthlink... From anywhere. At the time Earthlink was very popular, so that was not a good thing. In fact, the only reason why I found out was because half our office people were using Earthlink themselves. This went on and off for months and each time I had to start back off all over again with the "OK sir, is your computer plugged in?" line of questioning from the tech support people. And each time I had to desperately explain to them that it had nothing to do with our computers... Talking to chimpanzees would have accomplished more. Finally one night I got them to give me some manager guy, who after beating around the bush for 15 minutes finally admitted that they basically had no way of contacting anybody that actually worked with the system itself... As in, he had no contact... Period. None of them knew of any way to contact a human being in the whole company that could actually work on that kind of stuff. He said they tell them to submit problems by email to "The Nexus", but nobody knows who or where "The Nexus" is, and nobody has ever actually talked to a human being in "The Nexus". I pictured some Dr. Who type alien thing sitting in a room with all kinds of cables hooked up to his brain. Never did figure out what the deal was. The server people blamed earthlink and earthlink blamed the server people. We finally just changed our host and it stopped.

[maximillianos]

Ran into a similar problem a fee weeks ago. Had some random users unable to get to our server. Ever hear of the Bogon list? Google it. It is a list of reserved IP addresses. Most ISPs block them by default since they are commonly used in DDOS attacks.

Well the problem we found, as IP ranges get released from this list, if you don't update your firewall you may be blocking legit traffic. We checked our iptables and found our ISP had setup an initial block of all the Bogon IP ranges at the time they setup our server. Unbeknowst to us.

We just fixed and updated ours the other day. Now we stay on top of the list and when new ip ranges are released, we update our iptables.

[SteveWh]

Yes, it can happen that you can't reach your own site, but other people can. The two most common reasons I've seen are:

1) One of the "hops" between you and your website is temporarily down. Communication between you and your website normally passes through lines and other hardware belonging to multiple different companies. If any part of the path is down, you can't get through. People who get to your site via a different path won't be affected.

Nowadays, unlike the olden days, there is one defined routing path between any two points on the internet, and traffic is no longer sent along redundant paths or automatically rerouted when part of the net goes down. Rerouting traffic can still be done, but they're not going to bother doing it for an outage that lasts only a few hours.

The way to test if your path is good is to use the tracert (trace route) command. Open a Command Prompt (Windows):

C:\>tracert example.com

The output shows the hops in the path, and tells you if one of the nodes times out, meaning it is unreachable.

For help (not much):

C:\>tracert /?

2) If Windows discovers that a remote IP address is unreachable (especially, it seems, if it happens several times in quick succession for the same IP), it may log that information in its local DNS cache. For the duration of the time-to-live (TTL) of the cache entry (which could be an entire day), Windows will no longer even try to reach the remote IP address. Thus, if you have had problem #1 for a while (path down), Windows might still be unable to reach your site even after the path problem is fixed, because it's stopped trying.

The solution for this is to flush your local DNS cache, but it's simpler just to restart Windows, which does the same thing and is easier to remember how to do.