How to send mail from an OpenWrt router

I am using OpenWrt 10.03 and need to send "reports" from my router by email. I have installed sendmail:

# opkg install mini-sendmail

Then I used my ISP's smtp server:

# echo -e "From: [email protected]\nSubject: SUBJECT\nReply-to: [email protected]\n\nBODYHERE" \
> | mini_sendmail -sMYISPSSMTPSERVER [email protected]
mini_sendmail: unexpected response 550 to RCPT TO command

Questions:

1. How could I know, that my ISP's blocking port 25?

   # telnet MYISPSSMTPSERVER 25
   220 MYISPSSMTPSERVER ESMTP ready
   quit
   221 MYISPSSMTPSERVER closing connection
   Connection closed by foreign host
   

   so it's not blocked?

2. If port 25 isn't blocked, then how could I check this? Do I need an "email user" at my ISP?

3. If I can't get email working, than I have to register a free e-mail address [gmail?], and find out, how to send e-mail [with username and password required] in OpenWRT The only problem is that, I don't want to store passwords on the router.

Solution 1:

I know this is old, but it's one of the links that come up when searching "openwrt smtp"
Follow this link- https://forum.openwrt.org/viewtopic.php?id=18669

For sake of preventing linkrot issues..
First install.

# opkg install msmtp

Then create config file.

# cat /etc/msmtprc
account default

host smtp.gmail.com
port 587
auth on
user [email protected]
password password

auto_from off
from [email protected]

tls on
tls_starttls on
tls_certcheck off

logfile
syslog LOG_MAIL

To email, use the usual sendmail approach.

Solution 2:

Solution: I installed ssmtp + registered a free email address with ssl smtp as follows:

# opkg install ssmtp

$ cat /etc/ssmtp/ssmtp.conf
[email protected]
mailhub=SMTP.EXAMPLE.COM:465
rewriteDomain=EXAMPLE.COM
hostname=EXAMPLE.COM
FromLineOverride=YES
UseTLS=YES
AuthUser=MYEMAIL
AuthPass=PASSWORDHERE

$ echo -e "From: [email protected]\nSubject: SUBJECT\nReply-to: [email protected]\n\nBODYHERE" \
> | ssmtp -vvv [email protected]

Solution 3:

Can you take the router out of the equation and just send an email through telnet? ISPs will often block outbound SMTP (tcp/25) altogether while permitting connections to their mail server, which you can use as a smarthost (that might require authentication) to relay mail for you.