11 replies to this topic

[justanothernoob]

Hi. This is just a general question, probably obvious but, I just can't figure it out.

I have been working on a program that uses information from a bunch of different websites that are similar (they use the general same script). The sites all have been working and loading fine, until yesterday when around 33/40 of them just stopped working. It just won't load as if the site is down. At first I thought maybe somehow a lot of them were on the same server, and the server down, but today my friend said that that sites are working fine for him.

I tried connecting to the site on my roommates computer and it wouldn't load either. This made me think it was maybe it had to do with the school network.

I can access the sites through webproxies, but nothing will load if I try to access the one of the sites directly. I am on a university network, but I really don't know why the school would block the sites. They have to do with PTC sites. They aren't illegal or anything, and I don't think the school blocks anything anyway.

Any idea what could be causing this? Could it be related to malware or something?

Thanks.

[WingedPanther]

Sounds like they may have IP banned you, or your ISP may have blocked them. Most schools will block LOTS of sites, and will tell you if you tried to access a blocked site.

[Zizzy]

WingedPanther said:

Sounds like they may have IP banned you, or your ISP may have blocked them. Most schools will block LOTS of sites, and will tell you if you tried to access a blocked site.

What do you mean....

Quote

... and will tell you if you tried to access a blocked site. ...

...?

Do you mean the school will tell you/inform you that you have?

[WingedPanther]

IP ban: if a site believes your external IP (the college's network) was the source of an attack or abuse, it is common to configure their system to simply refuse ALL connections from that source. We actually have a similar feature on CodeCall so that if we ban a spammer, they can't just make a new account to try again.

Most proxy servers/filters (used by a school, for example) will show a message that you've attempted to access a forbidden site, if it's a violation. They also usually offer a link you can click to request an exception for the site.

[Zizzy]

Oh, I see. Yeah, my school does that; although Bluecoat is nearly the WORST proxy filter. Our school district uses Bluecoat, and... it absolutely just.. sucks. The students who have UltraSurf just bypass it anyway. :)

[RhetoricalRuvim]

WingedPanther said:

IP ban: if a site believes your external IP (the college's network) was the source of an attack or abuse, it is common to configure their system to simply refuse ALL connections from that source. We actually have a similar feature on CodeCall so that if we ban a spammer, they can't just make a new account to try again.

I still don't get it, don't ISPs change IP addresses around about every week or two? How would they know the bad person's new IP address?

[WingedPanther]

If you're logging in from a school, for example, your internal IP may change, but your external IP does not. So, for example, when I connect to a website, it can tell that I'm connecting from AT&T's network in the upstate of South Carolina, USA. If a site blocks THAT IP, a bunch of people get blocked. Since most companies/schools have a static external IP, it can be blocked pretty easily.

[RhetoricalRuvim]

What about residential networks?

So if person A has an IP address of 1.2.3.4 and goes and spams. Person A's IP address 1.2.3.4 gets blocked. Then Qwest or Comcast or AT&T changes IPs around (to keep them dynamic), in a week, and person B gets assigned to that IP address. Would person B be blocked now?

And what about people who have dial-up? Their IP is changed every time they connect.

[WingedPanther]

The thing is, A, B, C, and D will all share the same public IP address, and likely all get banned.

[RhetoricalRuvim]

Public IP address? Is that the IP address of the local area, or the ISP network? So either the whole neighborhood would get banned, or all the AT&T users would get banned, I think. What about dial-up users?

I'm not sure how this whole IP address thing works.

[mebob]

I guess it totally depends on your ISP, and your mode of delivery. In my area, with Charter cable internet, everyone has different public IP addresses. I've never dealt with dial-up or DSL, but it would make sense if they pooled together users with same IPs.

[WingedPanther]

My company dealt with some mail harvesting attacks recently. We blocked entire subnets to keep them out.