I wrote a Golang program that sends reports based on a ticker. Those reports are sent by mail using Postfix on a CentOS 7 machine. My problem is that the mail is sent successfully to users inside the same machine, but not to outside email addresses.
I tried this command:
traceroute -n -T -p 25 10.145.3.144
as seen here: Postfix: "Connection timed out" on all outbound email , and I get the same outcome:
1 * * *
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 * * *
which means, SYN packets are not getting SYN ACK packets back, but I believe the solution here might be different.
I also tried the ip route command, with the following outcome:
default via 10.87.161.17 dev eth0
10.87.161.16/29 dev eth0 proto kernel scope link src 10.87.161.18
After that, I tried changing the nameserver to 8.8.8.8(Google's) on the /etc/resolv.conf file but to no avail too as I am on a private company's network.
What can I change so that emails are sent correctly?
