We moved our DNS service to a different server and ever since, we periodically get a delivery failure due to this error. The IP address in the error message is our firewall. Why is MercuryC
complaining?
Message text:
The local mail transport system has reported the following problems
it encountered while trying to deliver your message:
-------------------------------------------------------------------
*** jsheffer@murdale.com
550 5.7.1 <jsheffer@murdale.com>... Relaying denied. IP name lookup failed [131.230.250.121]
------------------------------------------------------------------
MC070723.log entries:
E 20070723 090225 a68 550 5.7.1 <Genericusername001@gmail.com>... Relaying denied. IP name lookup fail
T 20070723 090359 a68 Established ESMTP connection to saluki-mailhub.siu.edu
T 20070723 090359 a68 Begin processing job MO005A9F from sofieb@pso.siu.edu
T 20070723 090359 a68 MAIL FROM:<sofieb@pso.siu.edu> SIZE=46704
T 20070723 090359 a68 250 2.1.0 <sofieb@pso.siu.edu>... Sender ok
T 20070723 090359 a68 RCPT TO:<Genericusername001@gmail.com>
E 20070723 090359 a68 550 5.7.1 <Genericusername001@gmail.com>... Relaying denied. IP name lookup fail
T 20070723 090432 a68 Established ESMTP connection to saluki-mailhub.siu.edu
T 20070723 090432 a68 Begin processing job MO005AAE from chrisg@pso.siu.edu
T 20070723 090432 a68 MAIL FROM:<chrisg@pso.siu.edu> SIZE=55020
T 20070723 090432 a68 250 2.1.0 <chrisg@pso.siu.edu>... Sender ok
T 20070723 090432 a68 RCPT TO:<jsheffer@murdale.com>
E 20070723 090432 a68 550 5.7.1 <jsheffer@murdale.com>... Relaying denied. IP name lookup failed [131.
T 20070723 090810 a68 Established ESMTP connection to saluki-mailhub.siu.edu
T 20070723 090810 a68 Begin processing job MO005ADD from nancyn@pso.siu.edu
T 20070723 090810 a68 MAIL FROM:<nancyn@pso.siu.edu> SIZE=1518348
T 20070723 090810 a68 250 2.1.0 <nancyn@pso.siu.edu>... Sender ok
T 20070723 090810 a68 RCPT TO:<tenac6pac@yahoo.com>
T 20070723 090810 a68 250 2.1.5 <tenac6pac@yahoo.com>... Recipient ok
T 20070723 090835 a68 Job MO005ADD from nancyn@pso.siu.edu processed OK.
T 20070723 090907 a68 Established ESMTP connection to saluki-mailhub.siu.edu
T 20070723 090907 a68 Begin processing job MO005AE2 from sofieb@pso.siu.edu
T 20070723 090907 a68 MAIL FROM:<sofieb@pso.siu.edu> SIZE=46960
T 20070723 090908 a68 250 2.1.0 <sofieb@pso.siu.edu>... Sender ok
T 20070723 090908 a68 RCPT TO:<genericusername001@gmail.com>
T 20070723 090908 a68 250 2.1.5 <genericusername001@gmail.com>... Recipient ok
T 20070723 090909 a68 Job MO005AE2 from sofieb@pso.siu.edu processed OK.
1. How have you configured mercuryC?
2. How is DNS set up on your network adapters?
3. Why do you not use MercuryE instead - since it appears you have a static address?
4. Depending on the smart host you use, they might be preventing you from sending since your DNS info regarding your firewall is out of synch, or that it lacks proper reverse pointers.
X. We need a little bit more to go on, the session log just confirms that the outbound IP you have set up, is sometimes deferred by the remote host - it might not be your issue at all, but the ISPs.
1. Configured MercC to use a smart-relay host, to use ESMTP and to log to MC~Y~M~D.LOG
2. we changed from our old DNS servers to our new ones which are actually just DNS forwarders for addresses outside of our internal network
3. tried MercE but mail didn't seem to be flowing correctly that way either. MercC just seemed easier to configure.
4. this gives me something to look into as our DNS info was adjusted as part of the installation of our new DNS servers
X. Hopefully, its just a reverse pointer that is needed, I'll check with our SIUC DNS admin
Thanks.
[quote user="chrisg@siuc"] 1. Configured MercC to use a smart-relay host, to use ESMTP and to log to MC~Y~M~D.LOG[/quote]
Hmm, I have to learn to be more specific when asking - sorry. Did you configure mercuryC to use a dotted domain name or did you use a direct Ip-number? Most likely a dotted domain host name, change this to a specific ip-number and proceed to fault find your DNS system.
Secondly, your NIC, is using a static address right? If so have you configured one or two DNS Ip-numbers?
Thirdly, you say DNS servers (pluralis) are these servers responding as they should, using regular lookups?
Most likely, now I'm guessing: is that you have the same DNS problems we have had at a customer site with forwarders. Turn on detailed logging on the DNS servers and examine the logs. Since you're using forwarding a query to the dns server should when the cache is outdated, go outbound to do get the resolution from an external server, or all the way over root hints. Regardless, a reply should come back from the external dns servers to your server, which in turn has to respond this query back to the client asking in the first place. In order to fault find what is going on, if you do not get a qeury response either externally, or internally back to the client - you need to examine the query path by verbose logging. A faulty router, a too strict firewall, packet fragmentation, cache poisoning etc can cause sporadic errors like these - or dns servers currently out of synch.
[quote user="chrisg@siuc"]We moved our DNS service to a different server and ever since, we periodically get a delivery failure due to this error. The IP address in the error message is our firewall. Why is MercuryC complaining?[/quote]
As you have gathered, it's not Mercury that's complaining, it's your relay host. I would ask the people who maintain saluki-mailhub.siu.edu and in particular, what they use for authenticating your relay.
(I see the relay host has two A records in DNS (possibly for load balancing), it may be that they don't respond the same way. That may explain why it's only an intermittent error.)
