RE: SMTP Error from my server?
> -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Jay Chandler > Sent: Monday, September 17, 2007 5:49 PM > To: freebsd-questions@freebsd.org > Subject: Re: SMTP Error from my server? > > > > > This idea works fine for normal email addresses, but fails miserably > > with certain types of automated email which is not intended for people > > to reply to, and it also tends to lose out with TDMA > > (http://tmda.net/). More importantly, it also fails to work with > > itself-- other people using "sender verification callouts" cause a > > loop of failed deliveries, as neither side trusts the other. > > > The larger problem as well is that it doesn't scale. Someone forging a > From header out of a botnet could easily DDoS a smaller server > completely off the net if enough people implemented this system. > verizon.net implements this system and they are pretty big. They put in checks to the setup to prevent these scenarios from happening. I don't like these systems myself as a gatekeeper but it isn't true that these systems cannot scale. They can scale fine - at the cost of greatly increased complexity of the logic in the system. I will point out that Network Address Translation - a technology that people take for granted and scale up all the time - has a far worse increase in complexity (espically in implementations that handle translation of all the normally not translatable protocols) I would actually love to see someone implement sender-callback-verification as a module in Spamassassin, where callback checks could be assigned a point value. In other words, failing sender-callback wouldn't automatically get a message blocked - but failing would increase the point value of the message to make it more likely to be considered spam. > Antispam measures that are in and of themselves abusive aren't generally > considered to be good ideas. It all depends on the implementation. A good implementation of sender callback is no worse than a good implementation of greylisting, and a bad implementation of sender callback is as bad as a bad implementation of greylisting. Ted ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Yep, white listing fixed the bounce. Thanks guys. Chris Maness ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Jay Chandler wrote: Chris Maness wrote: Chris Maness wrote: Jay Chandler wrote: Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Looks to me like a failed sender verification callout-- these are generally construed to be abusive. I can't easily tell from your munging whether it's your server or Adelphia that's doing it, though. This is the only e-mail address that I am having this problem with, and it has been going on for a year or so now. What other info would you guys need to tell what it is. I guess I don't understand the whole "sender verification callout" I'll have to do a little google to find out. Thanks, Chris Maness Sys Admin for a couple of tiny domains. p.s. I read up on this and I believe this would be a problem on the sender side. Is the something like an access file that I can change to just allow this particular sender without the check? Chris Maness Give me a bit of a hand here. Can you tell me what server the original message is being sent from, what server is kicking out that message, and which one you control? I don't need IPs, but call 'em Server A and Server B; the way you have it described is rather unclear. --J Thanks guys. I just white listed the sender and I will have the sender run a test to see if it works now. Thanks, Chris Maness KQ6UP ;o) ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Chuck Swiger wrote: The idea is pretty simple: when someone sends you an email, you delay accepting it until you can confirm that you can send a reply back to the sending address, or more precisely, check whether you can do a MAIL FROM: your domain and RCPT TO: the sender, and have it return OK, without actually going into the DATA phase and delivering a test message. This idea works fine for normal email addresses, but fails miserably with certain types of automated email which is not intended for people to reply to, and it also tends to lose out with TDMA (http://tmda.net/). More importantly, it also fails to work with itself-- other people using "sender verification callouts" cause a loop of failed deliveries, as neither side trusts the other. The larger problem as well is that it doesn't scale. Someone forging a From header out of a botnet could easily DDoS a smaller server completely off the net if enough people implemented this system. Antispam measures that are in and of themselves abusive aren't generally considered to be good ideas. -- Jay Chandler / KB1JWQ Living Legend / Systems Exorcist Today's Excuse: SCSI Chain overterminated ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
On Sep 17, 2007, at 5:25 PM, Chris Maness wrote: Can I turn it off for this sender? Presumably they or you can whitelist whichever address is being blocked, yes. I don't know which side is actually refusing the email as you've removed too much of the logging context to avoid revealing the client's email addy-- which isn't a bad reason, mind you, but it means we can't test it ourselves, so you'll have to fill in the details -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Chuck Swiger wrote: On Sep 17, 2007, at 4:05 PM, Chris Maness wrote: Looks to me like a failed sender verification callout-- these are generally construed to be abusive. I can't easily tell from your munging whether it's your server or Adelphia that's doing it, though. This is the only e-mail address that I am having this problem with, and it has been going on for a year or so now. What other info would you guys need to tell what it is. I guess I don't understand the whole "sender verification callout" I'll have to do a little google to find out. The idea is pretty simple: when someone sends you an email, you delay accepting it until you can confirm that you can send a reply back to the sending address, or more precisely, check whether you can do a MAIL FROM: your domain and RCPT TO: the sender, and have it return OK, without actually going into the DATA phase and delivering a test message. This idea works fine for normal email addresses, but fails miserably with certain types of automated email which is not intended for people to reply to, and it also tends to lose out with TDMA (http://tmda.net/). More importantly, it also fails to work with itself-- other people using "sender verification callouts" cause a loop of failed deliveries, as neither side trusts the other. ---Chuck Can I turn it off for this sender? Chris Maness ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Eric Crist wrote: On Sep 17, 2007, at 5:40 PMSep 17, 2007, Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Read the message... I'm guessing that [EMAIL PROTECTED] added NOSPAM to the beginning of the address to prevent SPAM from mailing list aggregators, et al. Remove NOSPAM from [EMAIL PROTECTED] and I'm sure you'll be fine. Also note that this is an error on the other end, nothing wrong with your server. - Eric F Crist Secure Computing Networks No, please read my message carefully. I changed it because I know this list gets harvested by spam bots because it is bridged to the usenet (Eric Crist wrote: On Sep 17, 2007, at 5:40 PMSep 17, 2007, Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Read the message... I'm guessing that [EMAIL PROTECTED] added NOSPAM to the beginning of the address to prevent SPAM from mailing list aggregators, et al. Remove NOSPAM from [EMAIL PROTECTED] and I'm sure you'll be fine. Also note that this is an error on the other end, nothing wrong with your server. - Eric F Crist Secure Computing Networks No, please read my message carefully. "I" changed it for this post because I know this list gets harvested by spam bots because it is bridged to the usenet (list.freebsd.questions). I did not want my client's e-mail to be picked up by spam bots. The actual e-mail in this header is a valid e-mail. Chris Maness ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
On Sep 17, 2007, at 4:05 PM, Chris Maness wrote: Looks to me like a failed sender verification callout-- these are generally construed to be abusive. I can't easily tell from your munging whether it's your server or Adelphia that's doing it, though. This is the only e-mail address that I am having this problem with, and it has been going on for a year or so now. What other info would you guys need to tell what it is. I guess I don't understand the whole "sender verification callout" I'll have to do a little google to find out. The idea is pretty simple: when someone sends you an email, you delay accepting it until you can confirm that you can send a reply back to the sending address, or more precisely, check whether you can do a MAIL FROM: your domain and RCPT TO: the sender, and have it return OK, without actually going into the DATA phase and delivering a test message. This idea works fine for normal email addresses, but fails miserably with certain types of automated email which is not intended for people to reply to, and it also tends to lose out with TDMA (http:// tmda.net/). More importantly, it also fails to work with itself-- other people using "sender verification callouts" cause a loop of failed deliveries, as neither side trusts the other. -- -Chuck ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Chris Maness wrote: Jay Chandler wrote: Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Looks to me like a failed sender verification callout-- these are generally construed to be abusive. I can't easily tell from your munging whether it's your server or Adelphia that's doing it, though. This is the only e-mail address that I am having this problem with, and it has been going on for a year or so now. What other info would you guys need to tell what it is. I guess I don't understand the whole "sender verification callout" I'll have to do a little google to find out. Thanks, Chris Maness Sys Admin for a couple of tiny domains. p.s. I read up on this and I believe this would be a problem on the sender side. Is the something like an access file that I can change to just allow this particular sender without the check? Chris Maness ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
On Sep 17, 2007, at 5:40 PMSep 17, 2007, Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Read the message... I'm guessing that [EMAIL PROTECTED] added NOSPAM to the beginning of the address to prevent SPAM from mailing list aggregators, et al. Remove NOSPAM from [EMAIL PROTECTED] and I'm sure you'll be fine. Also note that this is an error on the other end, nothing wrong with your server. - Eric F Crist Secure Computing Networks ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Jay Chandler wrote: Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Looks to me like a failed sender verification callout-- these are generally construed to be abusive. I can't easily tell from your munging whether it's your server or Adelphia that's doing it, though. This is the only e-mail address that I am having this problem with, and it has been going on for a year or so now. What other info would you guys need to tell what it is. I guess I don't understand the whole "sender verification callout" I'll have to do a little google to find out. Thanks, Chris Maness Sys Admin for a couple of tiny domains. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: SMTP Error from my server?
Chris Maness wrote: I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin Looks to me like a failed sender verification callout-- these are generally construed to be abusive. I can't easily tell from your munging whether it's your server or Adelphia that's doing it, though. -- Jay Chandler / KB1JWQ Living Legend / Systems Exorcist Today's Excuse: SCSI Chain overterminated ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
SMTP Error from my server?
I have not seen this error before. What does it mean? (I will change the actual e-mail to protect the address from spam bots). To: [EMAIL PROTECTED] From: Mail Administrator > Subject: Mail System Error - Returned Mail Date: Mon, 17 Sep 2007 14:48:17 -0400 This Message was undeliverable due to the following reason: Your message was not delivered because the return address was refused. The return address was "<[EMAIL PROTECTED]>" Please reply to Postmaster@ if you feel this message to be in error. Chris Maness Sys Admin ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
