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Mail from server in DMZ not reaching hotmail.com

Posted: Fri Jul 01, 2011 5:09 pm
by xalfeiran
Hi everyone

I have this situation, my Scalix server (Centos 5.2 and Scalix 11.4) is on a private network (192.168.2.117) and a fortinet firewall, acting as a DMZ. Public IP is on the 148.223.x.x network (static ip)

I'm having trouble sending email from scalix accounts and i think thats because of the private ip address, and hotmail ignores them.

Sending to hotmail gives me this on the mail-log

Code: Select all

Jul  1 15:34:35 centos sendmail[23055]: p61KYF6P023049: to=<mail@hotmail.com>, delay=00:00:19, xdelay=00:00:19, mailer=esmtp, pri=137750, relay=mx3.hotmail.com. [65.55.37.104], dsn=2.0.0, stat=Sent ( <001801cc382d$ebf09c80$c3d1d580$@mydomain.com.mx> Queued mail for delivery)


But with gmail, the mail goes all the way with no problem

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Jul  1 15:36:59 centos sendmail[23540]: STARTTLS=client, relay=gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL, cipher=RC4-SHA, bits=128/128
Jul  1 15:37:02 centos sendmail[23540]: p61Kau20023522: to=<mail@gmail.com>,<recipient@gmail.com>,<recipient2@gmail.com>, delay=00:00:05, xdelay=00:00:04, mailer=esmtp, pri=315878, relay=gmail-smtp-in.l.google.com. [74.125.113.27], dsn=2.0.0, stat=Sent (OK 1309552470 x2si2812762vds.150)


I know i have to change something on sendmail or scalix to be able to send messages using the public ip, not the private one.

any advice will be appreciated.

Xavier Alfeiran

PS. sorry for my crappy english :P

Re: Mail from server in DMZ not reaching hotmail.com

Posted: Sat Jul 02, 2011 8:59 pm
by les
xalfeiran wrote:Hi everyone

I have this situation, my Scalix server (Centos 5.2 and Scalix 11.4) is on a private network (192.168.2.117) and a fortinet firewall, acting as a DMZ. Public IP is on the 148.223.x.x network (static ip)

I'm having trouble sending email from scalix accounts and i think thats because of the private ip address, and hotmail ignores them.

Sending to hotmail gives me this on the mail-log

Code: Select all

Jul  1 15:34:35 centos sendmail[23055]: p61KYF6P023049: to=<mail@hotmail.com>, delay=00:00:19, xdelay=00:00:19, mailer=esmtp, pri=137750, relay=mx3.hotmail.com. [65.55.37.104], dsn=2.0.0, stat=Sent ( <001801cc382d$ebf09c80$c3d1d580$@mydomain.com.mx> Queued mail for delivery)


But with gmail, the mail goes all the way with no problem

Code: Select all

Jul  1 15:36:59 centos sendmail[23540]: STARTTLS=client, relay=gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL, cipher=RC4-SHA, bits=128/128
Jul  1 15:37:02 centos sendmail[23540]: p61Kau20023522: to=<mail@gmail.com>,<recipient@gmail.com>,<recipient2@gmail.com>, delay=00:00:05, xdelay=00:00:04, mailer=esmtp, pri=315878, relay=gmail-smtp-in.l.google.com. [74.125.113.27], dsn=2.0.0, stat=Sent (OK 1309552470 x2si2812762vds.150)


I know i have to change something on sendmail or scalix to be able to send messages using the public ip, not the private one.

any advice will be appreciated.

Xavier Alfeiran

PS. sorry for my crappy english :P


Its not that sendmail is sending from the private ip. Its more likely that sendmail is sending direct. This looks like the case in your example, gmail is different as it relays through the gmail smtp server gmail-smtp-in.l.google.com.
Hotmail probably doesn't like mail coming from the range....148.223.x.x

You should configure a SMART_HOST in /etc/mail/sendmail.mc so sendmail delivers via your ISP's smtp server. Then your mail will go through.

Re: Mail from server in DMZ not reaching hotmail.com

Posted: Mon Jul 04, 2011 12:09 pm
by xalfeiran
The problem is that this server is supposed to be my domain smtp server, so what if i need to send emails directly?

I must say, that this scalix server is very recent (two months) and before that we had a freebsd/postfix server running on the same public network, and besides other situation, sending emails to hotmail wasn't a problem.

thanks!

Re: Mail from server in DMZ not reaching hotmail.com

Posted: Mon Jul 04, 2011 6:32 pm
by les
xalfeiran wrote:The problem is that this server is supposed to be my domain smtp server, so what if i need to send emails directly?



Why do you need to send emails directly? These days you run the risk of remote servers who employ spam filters, blocking you because you come from a particular range of ip addresses, which could be seen as "bad sources" by internet based blacklists.

There is nothing wrong with forwarding mail through your isp's smtp server, or using an smtp forwarding service like dyndns.com provides (sendlabs gateway from memory). its par for the course if you want your mail delivered.

Also, even though it "worked before with postfix", that doesn't necessarily mean it'll work now. The problem is likely that hotmail has changed something, i.e. started using blacklists for spam filtering, which is out of your control.

Re: Mail from server in DMZ not reaching hotmail.com

Posted: Tue Jul 05, 2011 3:18 pm
by xalfeiran
The problem is that my ISP doesn't provide a very reliable SMTP relay system.

The other strange thing is that some of the scalix account can send mail to hotmail, but some others dont.

Re: Mail from server in DMZ not reaching hotmail.com

Posted: Tue Jul 05, 2011 7:26 pm
by les
xalfeiran wrote:The problem is that my ISP doesn't provide a very reliable SMTP relay system.

The other strange thing is that some of the scalix account can send mail to hotmail, but some others dont.


Then sendlabs gateway from dyndns.com is a good alternative to a crappy isp smtp server (or switch to business grade isp).

So, are you saying that for this single scalix account some mail gets to hotmail and others dont? or is it some mailboxes can send to hotmail while others cant? That is most likely down to content of the message, which scalix doesn't change, thats all done in outlook when the message is written.
Or, the hotmail user has marked the particular address that is trying to send as a junk sender.

try some tests...

send a blank message to the hotmail account from the affected user.
send a blank message to the hotmail account from an unaffected user.
etc