Hoaxblog.com

Today morning i was astonished to see, i have no email from our hosting support desk I thought, our service is becoming more pure and the customers are becoming more intelligent to handle the hosting service. Although, at night when i was handling a problem with a client, i found that, actually the mail server on sniper wasn’t working. I went to the Queue manager of WHM and found, there are 800+ emails waiting for being delivered. I tried to deliver them and received an error saying “host lookup did not complete”. I knew what kind of error is that, its usually happens when the root resolver doesn’t work for the server ISP. Sometimes it may occur for some internal issues for getting stuck after lots of run on named and apache. So i have tried to reboot the server and check whether it fixes or not. But unfortunately, it didn’t work. After that i tried checking the /etc/resolv.conf file and found that the private Ips configured are fine, but when i try to ping them from the server it doesn’t work, it doesn’t ping even google.com and any other domains too as its not being able to resolve anything.
So what i have done is stopping my firewall and checking whether it can ping the services or not, and kewla, it worked!! After that i tried to find some logs and found this that one of my client was spamming the whole server yesterday night using Exim. And as exim was using the root nameservers to control the mails, our automated ddos protector thought its an attack over the server and banned those ips automatically. Its quite crappy, but this is the second time i faced the same problem, last time when i faced it, i rebooted the server and it got fixed. I believe its because i was using IPTABLES at that time and i didn’t save the iptables rules, for that reason a reboot cleared those rules and fixed the problem Viola!!

Update: I found another case that, if the domain listed in /etc/remotedomains or not listed in /etc/localdomains then exim will reject from sending mails and pop will reject from receiving mails. So just adding the domain in /etc/localdomains and removing from /etc/remotedomains can also solve this problem