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LanceBaynes
Asked: 2011-01-20 12:38:37 +0800 CST

How to send mail from an OpenWrt router

  • 772

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.
linux email openwrt

4 Answers

  1. Best Answer

    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]
    • 4

  2. 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.

    • 4

  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.

    • 1

  4. Normally consumer Internet service providers will block TCP/25 for all SMTP servers other than their own. So it would be perfectly normal to be able to telnet to it from your router.

    Your ISP may require authentication before sending over SMTP and I do not believe mini_sendmail supports SMTP AUTH. You might look at ssmtp opkg instead of (or in addition to) mini_sendmail: http://linux.die.net/man/5/ssmtp.conf

    • 0