======== Required information ====
- iRedMail version (check /etc/iredmail-release):  0.9.4
- Linux/BSD distribution name and version: CentOS 7
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====

I've been searching for a proper answer but I couldn't find one.
The problem is that I'm not able to send mails from my server but I can receive mails.
I've done probably everything I can and I still cannot make things happen.

Here is an output of /var/log/maillog:

Mar 27 08:07:42 mail postfix/smtp[21230]: connect to mta6.am0.yahoodns.net[66.196.118.37]:25: Connection timed out
Mar 27 08:07:42 mail postfix/smtp[21231]: connect to mta6.am0.yahoodns.net[63.250.192.46]:25: Connection timed out
Mar 27 08:08:12 mail postfix/smtp[21230]: connect to mta6.am0.yahoodns.net[98.136.216.26]:25: Connection timed out
Mar 27 08:08:12 mail postfix/smtp[21231]: connect to mta7.am0.yahoodns.net[66.196.118.34]:25: Connection timed out
Mar 27 08:08:42 mail postfix/smtp[21230]: connect to mta6.am0.yahoodns.net[66.196.118.36]:25: Connection timed out

From what I've read so far, that's a network related issue, probably port 25 is blocked either by my edge router (not the case) or my ISP. I have talked to them and they claim that the port is open!

When i telnet to my own server i get a 220 reply and everything is working fine.
When i try to telnet to another server (either yahoo or google) the connection times out.

I start to think that my ISP is lying to me and don't want to open that port if I don't pay for premium account.

In case they're not lying. What would you suggest to do to get things working?

Here is a traceroute output just in case:

[root@mail ~]# traceroute -n -T -p 25 66.196.118.34
traceroute to 66.196.118.34 (66.196.118.34), 30 hops max, 60 byte packets
1  192.168.1.1  0.975 ms  0.955 ms  0.946 ms
2  * * *
3  * * *
4  * * *
5  * * *
6  * * *
7  * * *
8  * * *
9  * * *
10  * * *
11  * * *
12  * * *
13  * * *
14  * * *
15  * * *
16  * * *
17  * * *
18  * * *
19  * * *
20  * * *
21  * * *
22  * * *
23  * * *
24  * * *
25  * * *
26  * * *
27  * * *
28  * * *
29  * * *
30  * * *
[root@mail ~]#

I get a response from my router, but nothing after that as you can see.

Edit:

Eventually I gave up and end up using gmail servers as a relay host. The method works just fine, I can send mails through their server, but I really don't wanna do that.

If you have any suggestions, I'll be glad to hear them.

Thanks in advance!