Dnia 1.07.2020 o godz. 21:41:08 Ranjan Maitra pisze: > > I am using postfix to send e-mail. My home machine is called > xxx.sub.example.com (I am user with rm11) and my work email address is > r...@example.com. My ISP at home is not through my employer but I use VPN > through that. I use localhost as my smtp server and my e-mail address > as the sendmail address. This has worked fine but today I got the following > error/failure with two different recipient e-mail addresses. Here > are the error messages (similar for both): > > This is the mail system at host xxx.sub.example.com.
So the error is returned by Postfix on your home machine. > <x...@xxxx.xxx>: host mx.smtp.xxxx.xxx[ip] said: 554 5.7.1 R:DNS > - Message sourced from 70-81-125-2.client.isp.com [70.81.125.2] not > allowed. For assistance e-mail <h...@it.xxxx.xxx>. (in reply to RCPT TO > command) Is 70.81.125.2 the IP address of your home connection? It looks that your Postfix is trying to send mail directly from your home IP and got rejected, as many mail server administrators just outright reject connections coming from residential IP addresses, as an anti-spam measure. > Looking at the recipient webpage for the information (actually, quite > helpfully provided), I get: > > Your IP address appears on the SMTP gateway blacklist. This means that you > will not be able to send email messages directly from your computer > system to any address here that passes through the SMTP gateway. You will > need to use your ISP's mail servers to relay your email > messages. Please consult your ISP if you need assistance. That seems to confirm what I wrote above. > I am not sure what to do here, but would appreciate any advice. What I do not > understand also is if I use VPN, why does it go through the > ISP server which is blacklisted? It does not go through your ISP server. It goes directly from your home machine to the target server (via your ISP Internet connection of course), and it's your home IP address that is blacklisted (just because of being a home IP address). It doesn't matter that you use VPN to connect to your company's network, what matters is the fact how your VPN client sets up the routing table. For example in my case, when I'm connecting from home to my company's VPN, only connections to 10.0.0.0/8 go through VPN interface (my company uses that IP range for it's internal network), all other connections to the outside world go through my regular network interface, via my ISP directly to the Internet. It looks that this may be your case too. -- Regards, Jaroslaw Rafa r...@rafa.eu.org -- "In a million years, when kids go to school, they're gonna know: once there was a Hushpuppy, and she lived with her daddy in the Bathtub."
