Sendmail and ping

[The Alliance]

I am using sendmail 8.12.9 on an HP-UX system, any idea why sendmail would be pinging the destination IP address for the email connection? In the firewall logs I see pinging (tcmp-type 8, echo) - they are dropped - the destination IP shows up in the /var/adm/syslog/mail.log file.

[twang · Accepted solution]

Share a moment of time to take a look at this thread:
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x426b1012aa92d5118ff10090279cd0f9,00.html

[The Alliance]

Thanks twang, that helped. I now need to figure out why my config file is not been read on boot as the correct required value is in my configuration file.

Duane

[Steven E. Protter]

Note: There is no way you can successfully use sendmail to get email onto any public Internet smtp server if ping is required for contact.

Many mail servers either are firewalls or are passed traffic by firewalls that absolute block pings.

My little four computer web hosting company has a firewall box that does not respond to ping, but that box will very happy resolve and accept smtp mail traffic.

This is perhaps one of the reasons that HP has only gotten up to sendmail 8.11.1 on http://software.hp.com

I think this problem is resolvable, but they way I'd do it is get tested depots for 8.11 sendmail get current on security patches and use that product.

I don't think HP is going to be of much use, even if you have a software contract, that sendmail version isn't supported.

Best bet is to do this:

http://www.sendmail.org

There are links to help with HP there.

make sure dns resolution is rock solid

check /etc/nsswitch.conf
/etc/resolve.conf # make sure these servers are there and actually resolve addresses.

Even better would be the DS directive in sendmail.cf

DS
[IP_of_relay_server]


/sbin/init.d/sendmail stop
/sbin/init.d/sendmail start

Make sure the relay server will relay from the HP servers IP addy.

SEP