Very serious e-mail problems between Cpanel servers

[cruz]

Dear admin and advanced users of Cpanel,

I seriously need you help on this. I am a reseller of a hosting company and they uses several Cpanel servers. There is a serious e-mail problem in between different Cpanels that I reported months ago and is still not resolved by the hosting company.


(E-mail accounts in general)
The problem is that e-mail accounts setup on Server1 cannot be received at Server2, 3, 4.. etc. In other words, all e-mail accounts on the same server can communicate with each other, but any e-mail going to different servers are lost without any error message.

To put the story short, if I have 50 domain accounts setup on each servers, and each has 2 e-mail accounts. All 100 e-mail addresses' e-mails on Server 3 cannot be received at any e-mail account of other servers.

Please give any comment if you can. I seriously need a lot of help on this.

Thank you in advance!

[cruz]

I would like to add that the e-mail problem is only in between Cpanel server e-mail accounts. I could send and receive e-mails just fine with others like yahoo, hotmail, etc.

[PWSowner]

This might be related and possibly help you fix the problem.

I've had 2 instances in the last 1.5 years where I couldn't send or receive email between servers at the same datacenter. I noticed because I wouldn't get my billing emails at month end, or emails related to help desk tickets. My server providers site was on a different server in the same datacenter so I imagine the problem existed between my server and all others there.

Both times, here is what the helpdesk said and did.

for some reason the route:

209.xxx.xx.0 0.0.0.0 255.255.252.0 U 0 0 0 eth0

was on your server which prevented our server from connecting. I removed the route with the following command:

route del -net 209.xxx.xx.0/22 eth0

And the two servers are able to communicate again over the network.

I don't understand exactly what was done or what the problem was, but it fixed it both times. They said next time I can just run that command myself.

[cruz]

Thank you very much for your reply. Hopefully the data center is able to solve this problem.