Can ISP block selected e-mails?

[Cammacci]

Hi.

I'm not interested in legal aspect, just technical. I know it's not right. But there are still governments which practice censorship.

I'm not asking about spam filters. Those can be applied by mail service providers, which is different from ISP. Say my mail SP is Yahoo Mail, my ISP is Comcast for example. Comcast is not controlling Yahoo severs. But can control traffic from Yahoo server to me. Right?

The situation: ISP blocked a website. Now most likely it will try to filter subscribed distribution mail from this site.

Can an ISP filter my emails using information in the headers? The e-mail which I access through browser (not an e-mail client)

If yes, Can this be avoided?

Apparently I'll see the subject line, but will I'll be able to receive the body of the mail? The text? What if there is no text just attachment, say zip file?

 

[DiveCon]

Hi.

I'm not interested in legal aspect, just technical. I know it's not right. But there are still governments which practice censorship.

I'm not asking about spam filters. Those can be applied by mail service providers, which is different from ISP. Say my mail SP is Yahoo Mail, my ISP is Comcast for example. Comcast is not controlling Yahoo severs. But can control traffic from Yahoo server to me. Right?

The situation: ISP blocked a website. Now most likely it will try to filter subscribed distribution mail from this site.

Can an ISP filter my emails using information in the headers? The e-mail which I access through browser (not an e-mail client)

If yes, Can this be avoided?

Apparently I'll see the subject line, but will I'll be able to receive the body of the mail? The text? What if there is no text just attachment, say zip file?

no, they could block the website, but not the email content

 

[Cammacci]

Correct me if I'm wrong. For example yahoo doesn't encrypt traffic during sessions so any information which is passing through ISP can be processed and filtered. And even if there are no key words in the body of the message, there is lots on information in the header including senders IP.

 

[DiveCon]

Correct me if I'm wrong. For example yahoo doesn't encrypt traffic during sessions so any information which is passing through ISP can be processed and filtered. And even if there are no key words in the body of the message, there is lots on information in the header including senders IP.

ISP's dont have the capacity to filter at that level
you are being paranoid

 

[Cammacci]

I know examples. China, Uzbekistan and Iran. Recent reports were from Urumchi, China after clashes.

They do it some how? How?

 

[Luissa]

where did you get your name from?

 

[DiveCon]

I know examples. China, Uzbekistan and Iran. Recent reports were from Urumchi, China after clashes.

They do it some how? How?

they block the entire site

 

[KittenKoder]

Sites can block ISPs, ISPs can block sites or IPs, email is a bit different though ... it's complicated but let me see if I can explain it:

Email messages have two types of content, remote and local. Local content (such as text) is loaded directly to the server and stored there, that can be filtered only by the email host (if you block it you can't see the email at all). Remote content however is not actually on the email server (most images and multimedia files in your messages are remotely hosted and embedded in the email). These can be filtered by email server or blocked by your ISP or even blocked or filtered by you. Countries which control their ISPs (like China) filter the actual email servers, block sites, etc. before they get to you.

It would be possible for any ISP to choose to block any website they choose, but if your email server is not blocked the only things effected would be embedded content.

 

[DiveCon]

Sites can block ISPs, ISPs can block sites or IPs, email is a bit different though ... it's complicated but let me see if I can explain it:

Email messages have two types of content, remote and local. Local content (such as text) is loaded directly to the server and stored there, that can be filtered only by the email host (if you block it you can't see the email at all). Remote content however is not actually on the email server (most images and multimedia files in your messages are remotely hosted and embedded in the email). These can be filtered by email server or blocked by your ISP or even blocked or filtered by you. Countries which control their ISPs (like China) filter the actual email servers, block sites, etc. before they get to you.

It would be possible for any ISP to choose to block any website they choose, but if your email server is not blocked the only things effected would be embedded content.

which is why the efforts by China are not that successful

 

[KittenKoder]

Sites can block ISPs, ISPs can block sites or IPs, email is a bit different though ... it's complicated but let me see if I can explain it:

Email messages have two types of content, remote and local. Local content (such as text) is loaded directly to the server and stored there, that can be filtered only by the email host (if you block it you can't see the email at all). Remote content however is not actually on the email server (most images and multimedia files in your messages are remotely hosted and embedded in the email). These can be filtered by email server or blocked by your ISP or even blocked or filtered by you. Countries which control their ISPs (like China) filter the actual email servers, block sites, etc. before they get to you.

It would be possible for any ISP to choose to block any website they choose, but if your email server is not blocked the only things effected would be embedded content.

which is why the efforts by China are not that successful

Which is why China keeps trying to sue email hosts.

 

[Cammacci]

Sites can block ISPs, ISPs can block sites or IPs, email is a bit different though ... it's complicated but let me see if I can explain it:

Email messages have two types of content, remote and local. Local content (such as text) is loaded directly to the server and stored there, that can be filtered only by the email host (if you block it you can't see the email at all). Remote content however is not actually on the email server (most images and multimedia files in your messages are remotely hosted and embedded in the email). These can be filtered by email server or blocked by your ISP or even blocked or filtered by you. Countries which control their ISPs (like China) filter the actual email servers, block sites, etc. before they get to you.

It would be possible for any ISP to choose to block any website they choose, but if your email server is not blocked the only things effected would be embedded content.

Why I'm asking I had experience. In Uzbekistan I tried to open some of my messages but I was getting message from the ISP about an error. Those were plain text, but contained censored words like "Andijan" "massacre" "government". I could access the site, could log in and see the list of e-mails, but couldn't open some. While others were perfectly accessible. That was web-based service - yahoo mail.

 

[KittenKoder]

Sites can block ISPs, ISPs can block sites or IPs, email is a bit different though ... it's complicated but let me see if I can explain it:

Email messages have two types of content, remote and local. Local content (such as text) is loaded directly to the server and stored there, that can be filtered only by the email host (if you block it you can't see the email at all). Remote content however is not actually on the email server (most images and multimedia files in your messages are remotely hosted and embedded in the email). These can be filtered by email server or blocked by your ISP or even blocked or filtered by you. Countries which control their ISPs (like China) filter the actual email servers, block sites, etc. before they get to you.

It would be possible for any ISP to choose to block any website they choose, but if your email server is not blocked the only things effected would be embedded content.

Why I'm asking I had experience. In Uzbekistan I tried to open some of my messages but I was getting message from the ISP about an error. Those were plain text, but contained censored words like "Andijan" "massacre" "government". I could access the site, could log in and see the list of e-mails, but couldn't open some. While others were perfectly accessible. That was web-based service - yahoo mail.

You are talking about ISP censorship, which would block anything, even a text file, opened through the net with words that they censor. That is possible, just not commonly practiced due to the overhead in bandwidth usage and processor power. Smaller countries can accomplish such, but larger countries would not be able to accomplish it with the high amount of traffic. You could completely bypass such filters though, not hard really, which is another reason it's not commonly practiced.

 

[Cammacci]

Sites can block ISPs, ISPs can block sites or IPs, email is a bit different though ... it's complicated but let me see if I can explain it:

Email messages have two types of content, remote and local. Local content (such as text) is loaded directly to the server and stored there, that can be filtered only by the email host (if you block it you can't see the email at all). Remote content however is not actually on the email server (most images and multimedia files in your messages are remotely hosted and embedded in the email). These can be filtered by email server or blocked by your ISP or even blocked or filtered by you. Countries which control their ISPs (like China) filter the actual email servers, block sites, etc. before they get to you.

It would be possible for any ISP to choose to block any website they choose, but if your email server is not blocked the only things effected would be embedded content.

Why I'm asking I had experience. In Uzbekistan I tried to open some of my messages but I was getting message from the ISP about an error. Those were plain text, but contained censored words like "Andijan" "massacre" "government". I could access the site, could log in and see the list of e-mails, but couldn't open some. While others were perfectly accessible. That was web-based service - yahoo mail.

You are talking about ISP censorship, which would block anything, even a text file, opened through the net with words that they censor. That is possible, just not commonly practiced due to the overhead in bandwidth usage and processor power. Smaller countries can accomplish such, but larger countries would not be able to accomplish it with the high amount of traffic. You could completely bypass such filters though, not hard really, which is another reason it's not commonly practiced.

How it possible to bypass it? You mean proxy servers? I tried those in Yemen, it worked for a while, but then they stated to block them too. I couldn't make even one to work. People experience same in UAE, and Saudi Arabia. The irony here that US companies provide this technologies. For example in Yemen it's WebSense

What if there was no text in the body of the message? just an attached file, say zip or PDF, would it be possible to access it? Can provider block it?

 

[KittenKoder]

Why I'm asking I had experience. In Uzbekistan I tried to open some of my messages but I was getting message from the ISP about an error. Those were plain text, but contained censored words like "Andijan" "massacre" "government". I could access the site, could log in and see the list of e-mails, but couldn't open some. While others were perfectly accessible. That was web-based service - yahoo mail.

You are talking about ISP censorship, which would block anything, even a text file, opened through the net with words that they censor. That is possible, just not commonly practiced due to the overhead in bandwidth usage and processor power. Smaller countries can accomplish such, but larger countries would not be able to accomplish it with the high amount of traffic. You could completely bypass such filters though, not hard really, which is another reason it's not commonly practiced.

How it possible to bypass it? You mean proxy servers? I tried those in Yemen, it worked for a while, but then they stated to block them too. I couldn't make even one to work. People experience same in UAE, and Saudi Arabia. The irony here that US companies provide this technologies. For example in Yemen it's WebSense

What if there was no text in the body of the message? just an attached file, say zip or PDF, would it be possible to access it? Can provider block it?

I am not explaining how to bypass net security systems, especially in the open like this. However all files that are common formats can now be read through CGI/PHP/etc. scripts, which are the programming languages of the internet, so even they can be read, but again most countries or ISPs would not bother because it would be too expensive. It is possible to monitor streams though, which you could not bypass because they all monitor them a little for criminal activity, however you would also have to get their attention first. This is not a hackers forum, and good luck finding those (I got one closed down recently). I do not, nor does USMB staff, support criminal behavior and cannot assist in such. If the countries laws say that content is not allowed, that is their law.

 

[DiveCon]

You are talking about ISP censorship, which would block anything, even a text file, opened through the net with words that they censor. That is possible, just not commonly practiced due to the overhead in bandwidth usage and processor power. Smaller countries can accomplish such, but larger countries would not be able to accomplish it with the high amount of traffic. You could completely bypass such filters though, not hard really, which is another reason it's not commonly practiced.

How it possible to bypass it? You mean proxy servers? I tried those in Yemen, it worked for a while, but then they stated to block them too. I couldn't make even one to work. People experience same in UAE, and Saudi Arabia. The irony here that US companies provide this technologies. For example in Yemen it's WebSense

What if there was no text in the body of the message? just an attached file, say zip or PDF, would it be possible to access it? Can provider block it?

I am not explaining how to bypass net security systems, especially in the open like this. However all files that are common formats can now be read through CGI/PHP/etc. scripts, which are the programming languages of the internet, so even they can be read, but again most countries or ISPs would not bother because it would be too expensive. It is possible to monitor streams though, which you could not bypass because they all monitor them a little for criminal activity, however you would also have to get their attention first. This is not a hackers forum, and good luck finding those (I got one closed down recently). I do not, nor does USMB staff, support criminal behavior and cannot assist in such. If the countries laws say that content is not allowed, that is their law.

and not just the expense
the resources required to store that data would be MASSIVE

 

[Cammacci]

You are talking about ISP censorship, which would block anything, even a text file, opened through the net with words that they censor. That is possible, just not commonly practiced due to the overhead in bandwidth usage and processor power. Smaller countries can accomplish such, but larger countries would not be able to accomplish it with the high amount of traffic. You could completely bypass such filters though, not hard really, which is another reason it's not commonly practiced.

How it possible to bypass it? You mean proxy servers? I tried those in Yemen, it worked for a while, but then they stated to block them too. I couldn't make even one to work. People experience same in UAE, and Saudi Arabia. The irony here that US companies provide this technologies. For example in Yemen it's WebSense

What if there was no text in the body of the message? just an attached file, say zip or PDF, would it be possible to access it? Can provider block it?

I am not explaining how to bypass net security systems, especially in the open like this. However all files that are common formats can now be read through CGI/PHP/etc. scripts, which are the programming languages of the internet, so even they can be read, but again most countries or ISPs would not bother because it would be too expensive. It is possible to monitor streams though, which you could not bypass because they all monitor them a little for criminal activity, however you would also have to get their attention first. This is not a hackers forum, and good luck finding those (I got one closed down recently). I do not, nor does USMB staff, support criminal behavior and cannot assist in such. If the countries laws say that content is not allowed, that is their law.

Thanks. But you should know that in countries like that the governments are illegitimate and hold power by force. Dictators and their clans rob their own people. It's not hacking it's right to access any public information they need. It's freedom of speech. Can you imagine if comcast would start blocking access to Democratic Party's website because Republicans said so? Now think about Iran, Cuba, Yemen, Uzbekistan, Syria people die for freedom there, they die even when they criticize their corrupt governments. When I was in Uzbekistan I couldn't access to DP website because they refelcted on massacre by Uzbek government in Andijan. Was my activity criminal?

 

[KittenKoder]

How it possible to bypass it? You mean proxy servers? I tried those in Yemen, it worked for a while, but then they stated to block them too. I couldn't make even one to work. People experience same in UAE, and Saudi Arabia. The irony here that US companies provide this technologies. For example in Yemen it's WebSense

What if there was no text in the body of the message? just an attached file, say zip or PDF, would it be possible to access it? Can provider block it?

I am not explaining how to bypass net security systems, especially in the open like this. However all files that are common formats can now be read through CGI/PHP/etc. scripts, which are the programming languages of the internet, so even they can be read, but again most countries or ISPs would not bother because it would be too expensive. It is possible to monitor streams though, which you could not bypass because they all monitor them a little for criminal activity, however you would also have to get their attention first. This is not a hackers forum, and good luck finding those (I got one closed down recently). I do not, nor does USMB staff, support criminal behavior and cannot assist in such. If the countries laws say that content is not allowed, that is their law.

Thanks. But you should know that in countries like that the governments are illegitimate and hold power by force. Dictators and their clans rob their own people. It's not hacking it's right to access any public information they need. It's freedom of speech. Can you imagine if comcast would start blocking access to Democratic Party's website because Republicans said so? Now think about Iran, Cuba, Yemen, Uzbekistan, Syria people die for freedom there, they die even when they criticize their corrupt governments. When I was in Uzbekistan I couldn't access to DP website because they refelcted on massacre by Uzbek government in Andijan. Was my activity criminal?

It does not matter, the law is the law and in this part of the forum what is moral and legal is not up for debate. This subforum is only about computers.