Hot answers tagged

57

I'm going to put this as gently as I can: Wireless networks (802.11) suck. The 2.4GHz band (802.11b, g, and some n devices) is a festering pit of radio noise. Everything from baby monitors to microwave ovens pollute this section of the spectrum, and the wanton proliferation of wireless networks has it so congested that you're frankly lucky to get 1Mbit ...


48

For all intents and purposes, no, this is not possible. Even if it were, the technical and contractual logistics required would cripple your business. Think through this a bit more: Joe user at University signs up for your service. You then approach one of the University's many providers (which one? How might you know what provider Joe user's traffic ...


33

No, this is not normal. Contact your provider to resolve this issue. When they can't, switch away ASAP.


29

Depending on the frequency at which you exchange data with the customer, it could be cheaper, faster, and more efficient to mail them a storage drive, then pay to have it overnighted back to you when populated with data. This would cost a tiny fraction of what your agreement plan would cost long-term. Turnaround time may be nearly the same if lots of data is ...


24

As you already said: If I change my DNS to google DNS, the site can be viewed normally. So it has something to do with DNS. Your ISP provides his own DNS-Servers and he has a list of blocked domains. When you now query the IP-address of a blocked domain your ISP will not respond with the correct ip-address but with a ip-address of his own servers (or FBI ...


19

Here's the method that worked for me: Sync the files and databases with the new server. Perform a re-sync just before cut-off. Change the DNS to point to the new server. Forward the request coming to the old ip to the new server until DNS propagation completes. Here's how I would do the step 4: We will configure IPTables on a Linux server to redirect all ...


17

This is an unfortunate irritation. Multiple DNS servers are supposed to be to increase reliability, but in practice it frequently has the reverse effect. The problem is that the client only waits so long for a response, and the server waits about that same amount of time. Say you have two DNS servers, A and B. Say A is working and B has failed. This happens:...


17

It sounds like in effect you want to pay a users ISP to zero-rate traffic to your site, similar how to some cell carriers allow you to stream video from certain websites without impacting your allocation. If you are a major company like Google or Netflix then this has a ghost of a chance of being feasible, otherwise most companies will not talk to you -- ...


15

If you're an ISP, you really ought to have authoritative DNS servers that handle the reverse DNS for your networks. Not having them is somewhat akin to operator suicide; your biggest business customers are going to expect it, and if you don't have a contingency for this they're going to pack up their bags and move elsewhere. This isn't to say that you're ...


13

Please don't be offended, but if you don't know the answer to this question, you're not ready to do this. System and network administration at the service provider level requires some pretty in depth industry knowledge. The OSS/BSS involved (operational support systems, business support systems) alone could take years to learn. There's a reason why ...


13

That is indeed one of the problems with CGN. Sharing a resource means that all suffer the consequences when one abuses the resource. A bank that I consulted for implemented IPv6 on the server side exactly for that reason: more and more users end up behind CGN, hopefully also with IPv6. When their security department has to block an IPv4 address of a CGN, ...


12

It has been a while since I consulted to the telecom industry so I am going off of what is still likely. For DSL, this is sub-par. You should never see traffic destined for another IP address. I would check with your provider. This is not a standard configuration and it is likely that there are some settings in the RedBack that are not right. Each ...


11

I suggest you reevaluate your reasons for wanting to go the commercial route rather than using an opensource solution such as Squid. Squid is used by many large ISPs worldwide and is quite likely the most mature web cache and proxy available. Apart from the cost benefit of not requiring any license fees, Squid has an active community and hundreds of code ...


11

This is typical for enterprise-class internet connections provided by telcos. You manage your equipment, they manage their equipment (located at your site), and a clear demarcation point is provided at the router port that the telco provides for you to connect your equipment. Do they really need a $2000 router at every customer site? Probably not. What it ...


11

Answer: yes. Your browser will still promptly engage in the three-way TCP handshake with the server at ###.###.###.###, and your ISP can see that. Once the connection's set up, your browser will have an SSL handshake with the server, and your ISP can see that. Once session keys have been negotiated, your browser will continue to exchange SSL-encrypted ...


11

Usually for a large contract you should be able to negotiate at least read only access to their edge router. However even as building a new data center near one of our ISP connection (~40m cable) and a pretty big contract back then i was unable to get that. There was often some data leaking which you could get. Depending on your local laws this might ...


10

Back in college, we would use Vocalnet to broadcast such alerts. The investigator would stick his/her head out of the office door and shout "HEY EVERYBODY, THE INTERNET IS DOWN!" into the hallway.


9

StackExchange, as far as I know, own their own equipment, and host it in Peer1 datacentre in New York and another PEAK in Oregon. There's a big list of resources on this Meta.StackOverflow thread, with some excellent blog post links and as much data and serverporn as you can handle. Typically, a datacentre would have multiple connections to the internet - ...


9

The bottleneck I see when accessing that URL is clearly due to the window size. When I try to download from your server I get 555KB/s. I have a roundtrip time of 108ms. Doing the math I get the following window size: 555KB/s * 108ms = 59.94KB. As long as I do it from a host in a datacenter, I get a very consistent throughput and roundtrip. Additionally, if ...


9

I think there's slightly more complexity than mdpc suggests. The letter is true: only the person to whom the relevant chunk of PTR space has been delegated can manage the PTR records in that space. In the second paragraph they have made the assumption that the current delegate is the person who is responsible for the PA IP address space. That is usually a ...


9

The Wikipedia article on peering has a pretty comprehensive introduction. do ISPs always exchange traffic directly through Peering? No, although they may have direct connections with other networks for peering quite often they will use an internet exchange to facilitate peering, allowing an ISP to use a single connection to the IX to (potentially) peer ...


9

Lets' say that you have the website http://example.org. When you use your ISP's DNS servers it would resolve that domain to an IP address Since the ISP doesn't want you to see the website, they will let their DNS servers give you a different IP. On that IP address, they can host the page that shows you the warning message. The ISP does not alter your ...


8

I'd approach this from a different direction, sure you could do all manner of routing but why not pay Comcast to give you two static IP's - it won't cost too much more and you can just carry on as you were.


8

What do you have handy? If you have any emails from yourself, sent from home, the full headers will contain your IP address (maybe only if sent from a desktop client, not sent by webmail). Can you login to your ISP account page and find it? Do you have any servers you can connect into, and find "last logged in from {home IP}" in a logfile somewhere? Or ...


8

The dsn=2.0.0 and a correct relay= means that Bell's mail server has accepted the message. However, this doesn't mean that it will allow the message to be delivered to the user's mail box. In this instance the most likely explanation is that Bell South's spam filters have cleaned your message out before reaching the user's mail box or the user's own mail ...


7

This could very well be a switch/cabling issue, or a configuration problem on the desktop themselves. Anyway, a quick and easy test: take a laptop, plug it in socket A, download something big from a well-known high-bandwidth site (like Microsoft download center), measure time, move laptop to socket B, repeat, compare speeds. Also, while you're at it, you ...


7

It's not that unusual for large swathes of IP addresses to be blocked due to past or present problems with a particular provider or that particular netblock. Microsoft can pretty much block whatever they like as an email service provider. Their responsibility to their customers means they have to balance the problems caused by having a block against the ...


7

DHCP is of very little relevance to this question. With DHCP the ISP can tell the customer, what the address of the customer is. But between ISPs it works differently. Between ISPs communication about who has which IP addresses is done using BGP. In this context the networks are known as autonomous systems, to get an initial understanding it is a good ...


7

TLDR: No it is not possible because it is likely to be illegal in the country you are operating in. The proviso of course being that if you are in the US, the FCC/Trump are currently in the process removing the laws that protect users from the evils of such an arrangement. Net Neutrality Hi Ryan, I think you are asking the wrong question. Of course what ...


6

One of the primary providers of IP information is MaxMind. http://www.maxmind.com/ While they have many products, this one is their ISP database: http://www.maxmind.com/app/isp They have a number of interface methods as well (e.g. c library, apache module, php modules). The sites I've worked with have mainly used it for GeoIP purposes tied into web ...


Only top voted, non community-wiki answers of a minimum length are eligible