Changes have been made over our network …
Fresh out of managing the firewall course, guess what … we are having problems with our clustering firewalls ;P put right into the test … anyhow the problem seems to be momentarily solved, I’ll have to keep an eye on that one.
Some of emails are not going out and to some specific domain names (aol.com), the error message as follows:
Final-Recipient: rfc822; user@aol.com
Action: delayed
Status: 4.0.0
Diagnostic-Code: X-Symantec-Mail-Security; host
mailin-02.mx.aol.com[205.188.249.91] said: 421-: (DNS:NR)
http://postmaster.info.aol.com/errors/421dnsnr.html 421 SERVICE NOT
AVAILABLE (in reply to end of DATA command)
Will-Retry-Until: Sat, 14 Jun 2008 15:10:05 +0300 (AST)
If you go to the link, the basic issue that you don’t have any PTR records for your email agents that aol is trying to communicate with, they have a lookup tool to verify this which you can use. DAMN those dnsstuff for not being free anymore!!!
Some email servers for spam issues try to lookup the IP to get the host name
I’m new to the DNS thing, so when double checking out reverse zone, everything is configured properly … so the troubleshooting begins …
nslookup from any machine and connect to an external DNS server, your ISP’s and lookup your domain names and your IPs
It states to contact your ISP or DNS providers, so I thought we are our own DNS providers why aren’t the PTR updates reflecting outside!!!
Conclusion, to add any PTR record contact your ISP and they do it on their DNS.
So I called in and they transfered me from one to another, but they were really nice and finally I talked to this nice lady and I told her the requirements over the phone and hoooopppaaa everything configured.
Early morning, all pending emails have gone through
Along the way, I discovered a DNS configuration problem that apparently affected the Internet performance and now we increased 25%, hehehehe, OK, I need to stop and just hope the day “ye3adi 3ala khair”
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