port 25 block..

ROCKaMIC · 11-23-2004, 01:50 PM

I got a program that sends email by connecting to a smtp server..

the problem is.. what to do if the ISP of the user blocks all but the isp's smtp server??

there must be a loophole to it.. someway to go around this..

maybe someway to get the STMP server used by the user on windows registry (without relying on something like outlook, etc..)

Thanks!!

Devil Panther · 11-23-2004, 03:24 PM

connect directly to the dest. user's smtp server then!

you see, when you send a mail with your isp's local smtp server it gets forwarded to the destination's smtp server.

example:

you send to user@hotmail.com
from me@netvision.net.il

what happens is you send the mail with your local server: mailgw.netvision.net.il and it forwards it to one of hotmail.com's smtp servers (like mx1.hotmail.com).

in other words, you can simply send the mail directly to hotmail.com's smtp server!

goodluck.

ROCKaMIC · 11-24-2004, 08:46 AM

fixed some cases.. thanks

but what if the isp only gives access to their smtp server and none other?

:S

**Salem** · 11-24-2004, 09:20 AM

Probably to stop spammers

ROCKaMIC · 11-24-2004, 09:36 AM

Quote:

Originally Posted by Salem

Probably to stop spammers

Yes.

So the most ethic solution would be just find the default smtp of a computer.. somewhere in windows' registry or something.. no idea

Devil Panther · 11-24-2004, 11:40 AM

what do you mean by a smtp of a computer???

and about your isp blocking, well... your isp sucks, they have no right to do so! what are you living in china or something?!

**Salem** · 11-24-2004, 12:30 PM

> the problem is.. what to do if the ISP of the user blocks all but the isp's smtp server??
If the user can use their normal email client to send email via mail.myisp.com, then any program of yours which also conforms to RFC821 will also be able to send mail via mail.myisp.com
ALL mail goes via your local gateway, where it is then forwarded to the destination. You DONT connect directly to the destination address in order to send someone email.

Only incompetent and spam-friendly admins allow unknown persons to connect to mail.randomisp.com from which they can fake all their details and spam anyone they like with near untraceability.

Devil Panther · 11-24-2004, 12:54 PM

but you can act as a smtp server farwarding mail and connect the dest. smtp server yourself and send mail to it's user!

anonytmouse · 11-24-2004, 06:19 PM

>> If the user can use their normal email client to send email via mail.myisp.com, then any program of yours which also conforms to RFC821 will also be able to send mail via mail.myisp.com <<

I think ROCKaMIC is asking how you get the value "mail.myisp.com" without asking the user for it. ROCKaMIC, if you can convince me that you have a valid reason for getting this without asking the user, I can give you some hints. Your talk of a "loophole" doesn't exactly fill me with confidence.

For further information on why many ISPs block outbound direct email, see search: spam zombie.

Devil Panther · 11-25-2004, 10:12 AM

in other words he's looking for the user's smtp server's address.

you will need mx dns lookup for this:
network-tools.com

check the E-mail Validation, and type the user's e-mail address.
it will give a list of mx servers, that's the smtp servers for that domain.

w4ck0z · 11-28-2004, 01:46 PM

Hey 'RockaMic' would you be so kind as to show me your code used to send the email?
I've tried various ways using winsock, and I've not found a workable solution yet.

thank you

Devil Panther · 11-29-2004, 11:27 AM

you will need to learn the smtp commands, for a short and simple ref. i suggest: http://www.bsrf.org.uk/tutorials/sendmail.html

unless your problem is with network programming, because there isn't much to it, you just send these commands to the smtp server.

knutso · 12-11-2004, 02:15 PM

Here's some code i wrote a while ago that implements the RFC for smtp & MIME:

SMTP

Scroll to the end.

11-23-2004, 01:50 PM	#1
ROCKaMIC Registered User Join Date: Oct 2003 Posts: 21	port 25 block.. I got a program that sends email by connecting to a smtp server.. the problem is.. what to do if the ISP of the user blocks all but the isp's smtp server?? there must be a loophole to it.. someway to go around this.. maybe someway to get the STMP server used by the user on windows registry (without relying on something like outlook, etc..) Thanks!!
ROCKaMIC is offline

11-23-2004, 03:24 PM	#2
Devil Panther * Death to Visual Basic * Join Date: Aug 2001 Posts: 768	connect directly to the dest. user's smtp server then! you see, when you send a mail with your isp's local smtp server it gets forwarded to the destination's smtp server. example: you send to user@hotmail.com from me@netvision.net.il what happens is you send the mail with your local server: mailgw.netvision.net.il and it forwards it to one of hotmail.com's smtp servers (like mx1.hotmail.com). in other words, you can simply send the mail directly to hotmail.com's smtp server! goodluck. __________________ "I don't suffer from insanity but enjoy every minute of it" - *Edgar Allen Poe* http://www.Bloodware.net - Developing free software for the community.
Devil Panther is offline

11-24-2004, 08:46 AM	#3
ROCKaMIC Registered User Join Date: Oct 2003 Posts: 21	fixed some cases.. thanks but what if the isp only gives access to their smtp server and none other? :S
ROCKaMIC is offline

11-24-2004, 09:20 AM	#4
Salem and the hat of Jobseeking Join Date: Aug 2001 Location: The edge of the known universe Posts: 21,648	Probably to stop spammers
Salem is offline

11-24-2004, 11:40 AM	#6
Devil Panther * Death to Visual Basic * Join Date: Aug 2001 Posts: 768	what do you mean by a smtp of a computer??? and about your isp blocking, well... your isp sucks, they have no right to do so! what are you living in china or something?! __________________ "I don't suffer from insanity but enjoy every minute of it" - *Edgar Allen Poe* http://www.Bloodware.net - Developing free software for the community.
Devil Panther is offline

11-24-2004, 12:30 PM	#7
Salem and the hat of Jobseeking Join Date: Aug 2001 Location: The edge of the known universe Posts: 21,648	> the problem is.. what to do if the ISP of the user blocks all but the isp's smtp server?? If the user can use their normal email client to send email via mail.myisp.com, then any program of yours which also conforms to RFC821 will also be able to send mail via mail.myisp.com ALL mail goes via your local gateway, where it is then forwarded to the destination. You DONT connect directly to the destination address in order to send someone email. Only incompetent and spam-friendly admins allow unknown persons to connect to mail.randomisp.com from which they can fake all their details and spam anyone they like with near untraceability.
Salem is offline

11-24-2004, 12:54 PM	#8
Devil Panther * Death to Visual Basic * Join Date: Aug 2001 Posts: 768	but you can act as a smtp server farwarding mail and connect the dest. smtp server yourself and send mail to it's user! __________________ "I don't suffer from insanity but enjoy every minute of it" - *Edgar Allen Poe* http://www.Bloodware.net - Developing free software for the community.
Devil Panther is offline

11-24-2004, 06:19 PM	#9
anonytmouse Yes, my avatar is stolen Join Date: Dec 2002 Posts: 2,544	>> If the user can use their normal email client to send email via mail.myisp.com, then any program of yours which also conforms to RFC821 will also be able to send mail via mail.myisp.com << I think ROCKaMIC is asking how you get the value "mail.myisp.com" without asking the user for it. ROCKaMIC, if you can convince me that you have a valid reason for getting this without asking the user, I can give you some hints. Your talk of a "loophole" doesn't exactly fill me with confidence. For further information on why many ISPs block outbound direct email, see search: spam zombie.
anonytmouse is offline

11-25-2004, 10:12 AM	#10
Devil Panther * Death to Visual Basic * Join Date: Aug 2001 Posts: 768	in other words he's looking for the user's smtp server's address. you will need mx dns lookup for this: network-tools.com check the E-mail Validation, and type the user's e-mail address. it will give a list of mx servers, that's the smtp servers for that domain. __________________ "I don't suffer from insanity but enjoy every minute of it" - *Edgar Allen Poe* http://www.Bloodware.net - Developing free software for the community.
Devil Panther is offline

11-28-2004, 01:46 PM	#11
w4ck0z Registered User Join Date: Jul 2004 Posts: 24	Hey 'RockaMic' would you be so kind as to show me your code used to send the email? I've tried various ways using winsock, and I've not found a workable solution yet. thank you
w4ck0z is offline

11-29-2004, 11:27 AM	#12
Devil Panther * Death to Visual Basic * Join Date: Aug 2001 Posts: 768	you will need to learn the smtp commands, for a short and simple ref. i suggest: http://www.bsrf.org.uk/tutorials/sendmail.html unless your problem is with network programming, because there isn't much to it, you just send these commands to the smtp server. __________________ "I don't suffer from insanity but enjoy every minute of it" - *Edgar Allen Poe* http://www.Bloodware.net - Developing free software for the community.
Devil Panther is offline

12-11-2004, 02:15 PM	#13
knutso Registered User Join Date: Feb 2002 Posts: 328	Here's some code i wrote a while ago that implements the RFC for smtp & MIME: SMTP Scroll to the end.
knutso is offline

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