I tried to add a "email routing" in ispconfig 18.104.22.168 but failed. What I want to do is, abc.com and 123.com are different ispconfig-ed server, when abc.com is down, the 123.com will receive firstname.lastname@example.org
emails and deliver back to abc.com when abc.com up again. I already setup the MX 10 and MX 20 and nslookup correctly.
Then, I tried to telnet 25 mail1.abc.com (which will point to 123.com actually) with cmd mail from and rcpt to, but it replied "relay access denied". Is here the correct way to add in "email routing" or I need to edit the main.cf manually? Thanks.
below is the 123.com settings in email routing,
No MX lookup: yes
Dest: 22.214.171.124 (this is the mail.abc.com's IP)
Sort by: 1