Recently, we've upgraded our firewalls here at work and two of our boxes have been unable to send mail locally. Keep in mind that there is a route between the intranet (running sendmail) and the mail server (groupwise gwia).
Basically, any mail from our intranet or listserve have been able to send mail outside our network to the likes of yahoo, google, hotmail, etc. However, sending mail to our internal mail server is not working (this handles all mail for our domain). This has caused our not-for-profit clients to go crazy, but I've been forwarding a lot of it manually. So here's the issue. Whenever sendmail attempts to send out mail to our mail server we get the following error:
Jul 18 12:15:22 intranet sendmail: j6DK10iR032416: to=<email@example.com>, ctladdr=<firstname.lastname@example.org> (0/0), delay=4+21:14:22, xdelay=00:00:00, mailer=esmtp, pri=12900444, relay=email.mydomain.com., dsn=4.0.0, stat=Deferred: Connection timed out with email.mydomain.com.
Jul 18 12:15:22 intranet sendmail: j6DJ4q9X031388: to=<email@example.com>, ctladdr=<firstname.lastname@example.org> (48/48), delay=4+22:10:30, xdelay=00:00:00, mailer=esmtp, pri=13080949, relay=emaill.mydomain.com., dsn=4.0.0, stat=Deferred: Connection timed out with email.mydomain.com.
So, being the inquisitive guy I am, I checked the /etc/hosts file (btw this is RH EL 4) and everything seems to be setup correctly (this was working before):
127.0.0.1 s-intranet localhost.localdomain localhost
172.16.1.9 s-intranet intranet.mydomain.com
172.16.1.2 email email.mydomain.com
My sendmail.mc is also the same as it was before the upgrade:
dnl # This is the sendmail macro config file for m4. If you make changes to
dnl # /etc/mail/sendmail.mc, you will need to regenerate the
dnl # /etc/mail/sendmail.cf file by confirming that the sendmail-cf package is
dnl # installed and then performing a
dnl # make -C /etc/mail
VERSIONID(`setup for Red Hat Linux')dnl
dnl # default logging level is 9, you might want to set it higher to
dnl # debug the configuration
dnl define(`confLOG_LEVEL', `9')dnl
dnl # Uncomment and edit the following line if your outgoing mail needs to
dnl # be sent out through an external mail server:
dnl # The following allows relaying if the user authenticates, and disallows
dnl # plaintext authentication (PLAIN/LOGIN) on non-TLS links
dnl define(`confAUTH_OPTIONS', `A p')dnl
dnl # PLAIN is the preferred plaintext authentication method and used by
dnl # Mozilla Mail and Evolution, though Outlook Express and other MUAs do
dnl # use LOGIN. Other mechanisms should be used if the connection is not
dnl # guaranteed secure.
dnl TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
dnl define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
dnl # Rudimentary information on creating certificates for sendmail TLS:
dnl # make -C /usr/share/ssl/certs usage
dnl # or use the included makecert.sh script
dnl # This allows sendmail to use a keyfile that is shared with OpenLDAP's
dnl # slapd, which requires the file to be readble by group ldap
dnl define(`confTO_QUEUEWARN', `4h')dnl
dnl define(`confTO_QUEUERETURN', `5d')dnl
dnl define(`confQUEUE_LA', `12')dnl
dnl define(`confREFUSE_LA', `18')dnl
FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
dnl # The -t option will retry delivery if e.g. the user runs over his quota.
FEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnl
FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
dnl # The following causes sendmail to only listen on the IPv4 loopback address
dnl # 127.0.0.1 and not on any other network devices. Remove the loopback
dnl # address restriction to accept email from the internet or intranet.
dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
dnl # The following causes sendmail to additionally listen to port 587 for
dnl # mail from MUAs that authenticate. Roaming users who can't reach their
dnl # preferred sendmail daemon due to port 25 being blocked or redirected find
dnl # this useful.
# dnl DAEMON_OPTIONS(`Port=submission, Name=MSA, M=Ea')dnl
dnl # The following causes sendmail to additionally listen to port 465, but
dnl # starting immediately in TLS mode upon connecting. Port 25 or 587 followed
dnl # by STARTTLS is preferred, but roaming clients using Outlook Express can't
dnl # do STARTTLS on ports other than 25. Mozilla Mail can ONLY use STARTTLS
dnl # and doesn't support the deprecated smtps; Evolution <1.1.1 uses smtps
dnl # when SSL is enabled-- STARTTLS support is available in version 1.1.1.
dnl # For this to work your OpenSSL certificates must be configured.
dnl DAEMON_OPTIONS(`Port=smtps, Name=TLSMTA, M=s')dnl
dnl # The following causes sendmail to additionally listen on the IPv6 loopback
dnl # device. Remove the loopback address restriction listen to the network.
dnl DAEMON_OPTIONS(`[ort=smtp,Addr=::1, Name=MTA-v6, Family=inet6')dnl
dnl # enable both ipv6 and ipv4 in sendmail:
dnl DAEMON_OPTIONS(`Name=MTA-v4, Family=inet, Name=MTA-v6, Family=inet6')
dnl # We strongly recommend not accepting unresolvable domains if you want to
dnl # protect yourself from spam. However, the laptop and users on computers
dnl # that do not have 24x7 DNS do need this.
dnl (`confBIND_OPTS', `WorkAroundBrokenAAAA')dnl
dnl # Also accept email sent to "localhost.localdomain" as local email.
dnl # The following example makes mail from this host and any additional
dnl # specified domains appear to be sent from mydomain.com
dnl # masquerade not just the headers, but the envelope as well
dnl # masquerade not just @mydomainalias.com, but @*.mydomainalias.com as well
My next guess was that the firewall was blocking traffic on port 25. So, I telnet into the Groupwise box from the Intranet:
telnet 172.16.1.2 25
mail from: email@example.com
rcpt to: firstname.lastname@example.org
And low and behold I receive a message from the Intranet a few minutes later. This is extremely weird. I wrote a small perl script to call the sendmail command, but that mail never gets processed.
Restart the box you say, after scheduling down time, I restarted the server to no avail. The same problem persists. I've googled and searched through LinuxQuestions and although individuals have had similar problems I can't solve the problem. I think that maybe ICMP traffic between the two is being blocked, hence the (Connection timed out message). However I can't say for sure as our network guy is being most uncooperative saying the problem resides with our Red Hat Boxes.
Any questions, comments, suggestions, help would be most welcome.