TCP Configuration: Timestamp Option

The function of the timestamp option is fairly self explanatory, it simply lets the sender place a timestamp value in each and every segment.   In turn the receiver will also reflect this value in it’s acknowledgement which allows the sender to calculate a round trip time for every received ACK.    Remember this is indeed per ACK and not segment as this can include multiple segments.

Initially most implementations of TCP would only allow one RTT per window however this has changed and nowadays larger windows sizes need more accurate RTT calculations.   You can read about the definitions of these calculations in RFC 1323 which covers the TCP enhanced extensions that allow these improved RTT calculations. The time is estimated by sampling a data signal at a lower frequency one time per window which works well with smaller windows (and less segments).

Accurate measurement of data transmission is often very difficult in congested and busy networks also when troubleshooting across networks like the internet.  It’s difficult to  isolate issues and solve problems in these sort of environments because you have no control or access to the majority of the transport hardware.  For example if you are tryign to fix a Netflix VPN problem remotely being able to check the RTT is essential to analyse where the problems potentially lie.

The sender will place a 32 bit value in the initial field which will be echoed back by the receiver in the reply field. This will increase the size of the TCP header from 20 bytes to 32 bytes when this option is used. The timestamp value will increase value on each transaction. There is no clock synchronization between the sender and the receiver merely an increase in the value of the timestamp unit. Most implementations of the timestamp option recommend that the value increment in units of one ideally between 1 millisecond and 1 second.

This option is configured during the connection establishment and is handled the same way as the windows scale option in the previous section. As you may know the receiving connection does not have to acknowledge every data segment it receives. This however is simplified because only a single timestamp value is maintained per active connection which is updated according to simple algorithm.

First of all TCP monitors the timestamp value ensuring it has the correct value to send in the next ACK. The sequence number is updated after each ACK value is sent and not as it’s acknowledged. After a new segment arrives then the byte numbered in a variable called lastack is incremented. After a new segment arrives then this value is increased but the old value stored in a variable called tsrecent, When a timestamp option is sent the tsrecent value is sent, and the sequence number field is stored in the variable called lastack.

This means that in addition to the timestamp option allowing for better RTT calculation it also performs another function. The receiver can use the function to avoid receiving old duplicate segments using an addition feature called PAWS – Protection against Wrapped Sequence Numbers.

Further Reading on Commercial Proxy Options – http://www.anonymous-proxies.org/2017/05/buy-uk-proxy-ip-address.html

Security Specifications and Initiatives

Throughout the internet community, there are many groups working on resolving a variety of security related issues online.    The activities cover all aspects of internet security and networking in general from authentication, firewalls, one time passwords, public key infrastructure, transport layer security and much more.

Many of the most important security protocols, initiatives and specifications being developed can be researched at the following groups.

TCSEC (Trusted Computer System Evaluation Criteria)

These are requirements for secure products as defined by the US National Security Agency.   These are important standards which many US and global companies use in establishing base lines for their computer and network infrastructure.    You will often hear these standards referred to as the ‘Orange book’.

CAPI (Crypto API)

CAPI is an application programming interface developed by Microsoft which makes it much easier for developers to create applications which incorporate both encryption and digital signatures.

CDSA (Common Data Security Architecture) 

CDSA is a security reference standard primarily designed to help develop applications which take advantage of other software security mechanisms.   Although not initially widely used, CDSA has since been accepted by the Open Group for evaluation and technical companies usch as IBM, Netscape and Intel have aided in developing the standard further.  It is important for a disparate communication medium such as the internet to have open and inter-operable standards for applications and software.   The standard also includes an expansion platform for future developments and improvements in security elements and architecture.

GSS-API – (Generic Security Services API)

The GSS-API is a higher level interface that enables applications and software an interface into security technologies.  For example it can act as a gateway into private and public key infrastructure and technologies.

This list is of course, a long way from being complete and because of the fast paced development of security technologies it’s very likely to change greatly.   It should be remembered that although there is an obvious requirement for security at the server level,   securing applications and software on the client is also important.   Client side security is often more of a challenge due to different platforms and a lack of standards – configuration settings on every computer are likely to be different.

Many people now take security and privacy extremely seriously, especially now that so much of our lives involve online activities.  Using encryption and some sort of IP cloaker like this to provide anonymity is extremely common.  Most of these security services are provided by third parties through specialised software.   Again incorporating these into some sort of common security standard is a sensible option yet somewhat difficult to achieve.

Further Reading: Netflix VPN Problem, Haber Press, 2015

Certificate Based Client Authentication

One of the most important features of SSL is it’s ability to authenticate based on SSL certificates.  Often people fail to understand that this certificate based authentication can only be used when SSL is functioning, it is not accessible in other situations.    Take for example the more common example on the web of insecure HTTP exchanges – this means that SSL certificate based authentication is not available.  The only option here is to control access by using basic username password authentication.  This represents possibly the biggest security issue on the internet today because this also takes place in clear text too!

Another common misconception is with regards the SSL sessions themselves.  SSL sessions are established between two endpoints.  The session may go through a SSL tunnel which is effectively a forward proxy server.    However secure reverse proxying is not SSL tunnelling it’s probably better described as HTTPS proxying although this is not a commonly used term.   In this example the proxy acts as an endpoint of one SSL session, accepting the endpoint of one SSL session and forwarding the request to the origin server.

The two sessions are distinct except of course they will both be present in the cache and memory of the proxy server. An important consequence of this is that the client certificate based authentication credential are not relayed to the origin server.   The SSL session between the client and the reverse proxy server authenticates the client to the proxy server.  However the SSL session between the origin server and the proxy authenticates the server itself.   The certificate presented to the origin server is the reverse proxy’s certificate and the origin server has no knowledge of the client and it’s certificate.

Just to summarise this is the ability to authenticate the client to the origin server though the reverse proxy server.

In these situations where client based certificate based authentication and access control are required, the role would have to be performed by the reverse proxy serve.  In other words the access control function has been delegated to the proxy server.  Currently there is no protocol available for for transferring access control data from the origin server to the reverse proxy server.    However there are situations in advanced networks where the access control lists can be stored in an LDAP server for example in Windows Active directory domains.   This enables all unverified connections to be controlled, e’g blocking BBC VPN connections from  including outbound client requests to the media servers.

The reverse proxy could be described in this situation as operating as a web server.  Indeed the authentication required by the reverse proxy is actually web server authentication not proxy server authentication.    Thus crucially the challenge status code is HTTP 401 and not 407.  This is a crucial difference and a simple way to identify the exact authentication methods which are taking place on a network if you’re troubleshooting.

 

Buy US Proxy with Transparent Proxying

When we are discussing the technological characteristics of proxies there’s one term which you will see used very often – ‘transparent’.    It can actually be used in two distinct ways when it comes to proxies.  The first is to refer to a definition which implies transparent proxying ensures that any user will see no difference to the original request whether it goes direct to the server or through a proxy.   In an ideal world pretty much all legitimate proxies would be considered ‘transparent’.

Proxies are however significantly more advanced from the early years when this original definition was created.  The term ‘transparent proxying’ now has much more meaning.  The extended definition means that transparent proxying ensures that the client software is not aware of the existence of the proxy server in the communication stream.   This is unusual because the client was usually configured to use a proxy, perhaps by the internet settings in it’s browser configuration.    Software would then make a decision in it’s requests and perhaps distinguish between proxy and direct requests.

When transparent proxying, in it’s modern context, is used the router is programmed to redirect the request through the proxy not the client. This means that the proxy can actually be used to intercept and control all HTTP requests that are targeted by outbound connections.  The request can even be parsed or perhaps even filtered and redirected.  This control allows the network to configure access control rules on all outbound requests,  A company network could use these to ensure unsuitable requests are not being made from a corporate network e.g. illegal web sites.

This level of transparent proxying leaves the client completely unaware of the existence of an intermediate proxy server.   There are some caveats though and the proxy can be detected in certain circumstances.  For  example there is little point in investing in a USA proxy buy if the server only supports HTTP/1.1 because the protocol makes no allowance for transparency in proxying information.

One of the main issues and indeed worries is that allowing completely transparent proxying might cause other issues particularly in the client side applications.  For example one of the fundamentals of using proxies in a corporate network is to reduce traffic by caching locally.  This could cause all sorts of problems if the behaviour of the proxy cache effects communication between the destination server and the client application.

Further Reading – http://www.changeipaddress.net/us-ip-address-for-netflix/

Remote Login Methods

The ability to remotely login to a machine that’s miles away from you is perhaps one of the internet’s most popular applications.  It might not seem so, but being able to access a remote host without a hard wire connection has transformed many areas of IT particularly in support and development.   Obviously you need an account on the host that you are trying to login to, but actually using the machine as if you are at the console is extremely useful in many situations.

Two of the most famous applications for remote login access when using a TCP/IP based network (e.g like the internet) are Telnet and Rlogin.   The most famous and probably used by every IT support technician over the age of 25 is Telnet, installed as standard in almost every TCP/IP implementation.   It seems relatively simple but this actually hides some great functionality not least the ability to Telnet from one operating system to another.  It’s incredibly useful to be able to sit at a Microsoft Windows machine with multiple command interfaces open in separate windows to Unix and Linux machines at the same time.

Remember these terminal windows are actually like physically sitting at the remote host’s console.  This is is completely different from just using a web session or using something like an Italian to stream RAI player abroad like this.  Each individual character that you type is entered into the remote host, there’s no streaming, no relaying or filtering.  Obviously there are some restrictions about running a terminal windows on a completely different systems.  However Telnet does an option negotiation phase between the client and server to ensure that only services which are supported at both ends are available.

The other famous remote login application is called Rlogin which was developed from Berkeley Unix.   This application was initially only available on Unix Systems however it has been ported to most other operating systems now and you can Rlogin between Windows and Linux.  Both of these applications use the Client/Server configuration – the client is the system where the initial connection is established to the remote server which is the target.

Nowadays, the most popular of the two application – Telnet has become much more sophisticated.  Over the years lots of functionality has been added to Telnet whereas Rlogin remains quite simple and unmodified.  However it should be noted that although Rlogin lacks features, it is a simple and stable remote access application.

The author – John Herrington has worked in IT for over thirty years in a variety of roles from support to latterly Network manager at a large bank.   He now works for himself and runs one of the largest paid VPN services on the West Coast of America. He obviously works remotely a lot of the time but will rarely use Telnet as it’s too insecure!

Tracking VPN and Proxy Users

There are similar challenges for network administrators in corporate networks and those running firewalls for authoritarian regimes about the use of proxies and VPN services.  The issue is that not only do they allow individuals the freedom to conduct their internet activity without being tracked, a VPN will also prevent most aspects of logging taking place too.

If you imagine a company network it means that an individual could potentially conduct all sorts of behaviour from a company computer whilst sitting in a corporate office whilst at work.   They could be downloading films, streaming Netflix or something perhaps much more sinister even.  Obviously this is potentially a risk to both the network infrastructure and also potentially to the company’s reputation.

So how do you block the use of VPNs and proxies?  For a corporate network there are actually many more options, and the simplest is probably to stop any sort of VPN and proxy being used in the first place.   You can lock down the advanced settings in a web browser quite simply, for example the Internet Explorer Administration Kit (IEAK) allows you to configure and deploy an IE package which cannot be modified onto every client in your organisation.  This stops proxies being used manually and VPN clients can be blocked by ensuring that  standard users have no administrative access to their desktops.

It is certainly easier to block any installation than trying to track the use of VPNs particularly some of the most sophisticated ones.   For example although you could potentially monitor logs in firewalls and routers for specific IP addresses which looked like VPNs some services allow you to switch to a range of IP addresses – Hide My VPN like the one in this video demonstrates:

As you can see if a service is rotated then identifying the VPN by it’s IP address is much more difficult.  However blocking installation of the highlighted service Identity Cloaker can also be difficult as it has a mobile version which can be run directly from a USB disk.

You can see that proxies are fairly irrelevant today as they can be easily blocked, also most content filters can detect their use too.   Significantly their use has now dropped globally for additional reasons mainly that they are mostly detected by websites which operate regional restrictions.   It is the more sophisticated Virtual private networks which are the difficulty, particularly those equipped with various VPN hider technologies and advanced encryption.

VPN Blocking on the Rise

For years people have used VPNs for all sorts of reasons, but it’s origin lay quite simply in the security they provided.  International companies will normally insist that their employees use VPN services when remotely connecting back to their servers using the internet.  It makes sense, otherwise important information and credentials would be trusted to the owners of coffee shop wifi or the administrator of your local Premier Lodge or hotel chain.

The concept is simple, create an encrypted tunnel which ensures that all the data which normally is passed in clear text instead is encrypted and unreadable.  Of course, this security means that as well as being safe from computer criminals and identity thieves – it’s also secure from intelligence services and state controlled snoopers too.  It should come as no surprise that anyone who opposes free speech generally hates VPNs and the protection that they give.

So when we hear stories about different organisations and companies from the Netflix to the Chinese Government trying to block VPNs what are they doing.  Well it depends, obviously the situation that leads to thousands of BBC iPlayer VPN not working is going to be slightly different to the Chinese throwing billions at the great firewall of China.   However the general techniques are basically the same as a small company want to achieve the same thing.

One of the most common options is to block the ports used by these services.  Most VPN tunnelling protocols operate on standard ports, e.g using PPTP or LTP.  They need to establish these connections to transfer and receive data, without them the service won’t function.  Other methods include identifying and blocking specific IP addresses or ranges which are being used by VPN services.   It is these two methods that are mostly used by the big media companies like Hulu and the BBC.

These methods can be time consuming though and it’s possible to switch address and some services allow you to configure alternative ports too. The Chinese Government as you would expect have gone one step forward and use more sophisticated techniques like deep packet inspection.   These involved looking at the data itself to identify if a VPN is being used to transport it.  For example if you are unable to read any data because none of it’s in clear text then there is the likelihood that it is being encrypted.   Of course, there are other methods which encrypt data like SSL so you need to be careful that you don’t block other traffic, it’s a risk that the Chinese would probably be happy to take however.

Even these methods are not foolproof and VPN companies can scramble things like the meta data to make identifying the use of a VPN even harder.  It is worthwhile noting that many people in China still use VPNs routinely and so if the huge resources available to the Chinese State can’t block their use – we should be ok to have a BBC VPN like this for the foreseeable future.

 

 

BBC News Streaming from Outside the UK

The BBC haven’t always streamed the BBC News over the internet, in fact it was noticeably missing from the initial releases of the BBC iPlayer for a few years. There are a few other programmes which were omitted, for example there was always a delay put on Match of the Day presumably for contractual reasons. However now that BBC has it’s own dedicated 24 hour News channel, it’s great news to see that it’s simultaneously broadcast live online on their web site.

You can see the tab illustrated which leads to the live TV streaming section including the BBC News channel.   However many people outside the UK will have problems finding this link as it simply doesn’t exist on the version you get outside the UK.  It’s called the ‘International version’ and anyone not in the UK will be redirected to this site.   The site is good but it’s missing all the TV stations and the BBC iPlayer functionality, even if you go there directly you’ll get blocked whenever you try and play anything.

Here’s a quick video entitled – BBC News Streaming over the Internet which you can also watch below:

As you can see the trick is to hide your location before you connect to the website. By logging on to a server physically located in the UK, you can access any of the BBC without issue simply because it will see the server’s UK address and not your real one. It has the added bonus of adding a layer of security and privacy to your internet connection too. This is because the connection between your computer and the VPN server is entirely encrypted which means both your identity is private but also all credentials you pass through the VPN are safe too.

It should be added that all the media companies try and block access to their sites through intermediary servers like proxies and VPNs. However there are still several companies who’s servers work perfectly well for accessing the BBC from anywhere in the world.

Further Reading – http://bbciplayerabroad.co.uk/bbc-news-streaming-abroad/

Irish Proxy for Watching RTE PLayer Live

RTE is the national broadcaster of the Republic of Ireland and has been involved in broadcasting TV channels since 1961.  It was actually an early adopter of radio broadcasting yet Ireland was relatively slow in getting involved in TV broadcasts – the BBC was involved in the 1920s for example.  There was some television broadcasting in Ireland through the Northern Ireland services run by the BBC although this was completely unofficial.

The Irish Government until the late 1950s considered TV to be a luxury which wasn’t a priority however it changed it’s opinion as the popularity rose.  A committee was formed to investigate how to set up an Irish broadcasting service (for the lowest possible outlay) and it’s initial form was something like the commercial services from the UK.

The first broadcast was on New Year’s Eve, 1961 at 19:00 hours and included a speech from the President who described what the service would be.   Many other messages were then broadcast from religious figures before a live concert was shown live from the Gresham Hotel in Dublin.

Irish proxy

Temple Bar, Dublin

The Irish people took to the new medium almost immediately particularly as a way to discuss topics and current affairs.   Suddenly topics like abortion, religion and contraception were discussed openly in chat shows and tv studios broadcast across Ireland.  The origin of many of these chat shows lies with the first and arguably the most famous one – The Late Late Show which began in July 1962 and which still runs today.

Although RTE was relatively late to the world of TV broadcasting, however it caught up quickly.  In 1962, RTE expanded it’s broadcasts to include 625 line transmissions several years ahead of the BBC for instance.  In 1969, RTE broadcast the Wimbledon finals in colour over the next few years more and more broadcasts were transmitted in colour.

Rte has expanded it’s channels over the last few years and also branched out into the world of internet broadcasting. RTE Player is the channels broadcasting application and it can be found at the following address – http://www.rte.ie/player/.

Unfortunately the channel is not directly available over the internet outside Ireland although they can be accessed in certain areas. You can watch RTE player in UK but only from certain areas of Northern Ireland particularly near the border there is some overspill of the signal. Also the channels were made available over Sky although there has been some disputes over licensing so certain events usually sports shows are not available in Northern Ireland.

There is however a method where you can watch RTE Player from outside Ireland.   This involves hiding your location behind an intermediate server which means that you can appear to be from whatever country you require.  To do so you don’t need to teleport to Ireland you just need to get hold of an Irish IP address.  So to access RTE Player you would merely connect through to an Irish proxy server first there is also an explanation here – http://www.iplayerabroad.com/bbc-iplayer-ireland/. This actually means your location is irrelevant, by using an Ireland proxy online you can be anywhere, you can even watch Irish TV in Spain for example.

What happens is that the proxy acts as a buffer between the RTE web site and your computer.   When the website performs a lookup on the connecting IP address it will receive that of the server and not the client.  As long as that server is based in the Republic of Ireland then all of the RTE website will be accessible through an Ireland web proxy.

This method works for all geo-restricted sites although there are a few exceptions.    Many websites now are able to detect and block the use of proxies, and most users have switched to using VPN.  These encrypted and secure services are much more difficult to detect than simple proxy servers and can be used in the same way to hide a user’s physical location.

Although at the time of writing the Irish proxy still works, it is becoming unreliable. It is strongly suspected that the proxies will be blocked at some point and if you want to watch rte in UK you’ll need to invest in a VPN with an Irish IP address list. The VPN is almost impossible to detect and you can also use it on any device, it’s fairly easy to set up an Irish vpn for ipad or an Ireland vpn for Android devices for example.

If you’re looking for a mixture of high security and fast servers, then may we suggest trying out Identity Cloaker.   It’s an amazing program with servers in the US and most European countries including Ireland and UK.

Try the 10 day trial out here to see how good it is. 

Using a Proxy to Watch the BBC Iplayer in USA

You’d never hear the word ‘proxy’ outside of an IT department a few years ago, but now everyone uses them. This post is specifically how to use a proxy to watch the BBC iPlayer application in the USA. Now firstly a quick introduction to the problem, the internet is not open or unrestricted in fact it’s more compartmentalised than ever before. One of the reasons, is a technology called ‘region locking’ or ‘geo-targeting’ which have very similar meanings.

These technologies are basically designed to ensure that certain websites are only accessible from specific physical locations. It sounds crazy, but it’s true – where you are based physically has a huge impact on what you can access online. I’m not talking about the stupid filtering that paranoid governments do either, these restrictions are deployed by the web sites themselves. Mostly it’s to do with money, profit or copyright laws but they affect a huge proportion of the world’s best web sites.

I would certainly put the BBC and it’s application BBC iPLayer as one of the best web sites on the internet. You get access to all the BBC broadcasts live, something like six or seven 24 hour TV channels plus all the radio channels. You can also watch stuff for about six weeks after using the BBC iPlayer, all quality programmes with not an advert to be seen. Unfortunately it’s only accessible in the UK, if you try and access from the USA you’ll get blocked.

Which is where our friend the proxy comes in, a server that sits between you and the web site you visit basically hiding your real location. The trick is to use a proxy server that sits in the country you need access to, which for the BBC is of course the United Kingdom.

So here we go – How to watch the BBC iPlayer USA simply by using a proxy server.

As you can see this is on a computer, the software demonstrated is called Identity Cloaker and actively hides your true location when you visit any website. In this instance, the BBC sees the UK proxy server and assumes that is your location and as such everything works, you can even watch the BBC News.

Now a few years ago pretty much any proxy server would work, even the free ones you could find online. However this has now changed and there’s a few things you should bare in mind when looking for a way to watch the BBC iplayer in the USA.

Speed – it’s everything when streaming video, otherwise whatever you’re watching will buffer all the time.
Discretion – don’t sign up to a proxy/vpn service which openly advertises bypassing the BBC blocks and has it’s logos all over the site. They will get blocked or closed down.
Security – last year the BBC started actively blocking these connections from proxies. They need to be securely configured so as not to be detected.
Other Countries – If you want to access websites and TV stations in other countries, you’ll need access to proxies in those countries too.

Identity Cloaker is our recommendation because of it’s speed and security, plus it’s very reasonably priced.   Try the 10 day trial first to make sure it works well for you.  Although the core program is software to run on your computer/laptop you can also connect through from a tablet or smartphone by creating the connection manually.  It’s easy to do and there’s a guide here.