I can access it fine when on wifi, but when I go onto 4G (or 3G), my e-mail fails to connect to the server. I tried this even sitting watching the logs on the mail server. When on 4G, it never sees it attempt to connect to the IMAP server. On wifi, I see the proper connection and authentication messages in the logs.
Currently set-up to do IMAP over port 993 with SSL.
Is there something I missed (a setting or something) that is causing this? Is verizon blocking packets on their end of the network?
Solved! Go to Correct Answer
I have fixed it from my end.
Seems to have been an issue with IPv6 (AAAA) records in DNS getting mangled. The AAAA record is set to the correct address, but verizon seems to run it through an IPv6 -> IPv4 conversion of some sort. The problem was it wasn't converting it to the correct IPv4 address. Instead, it pointed me to a third party instead. All of the traffic went to this server, which isn't currently running any mail server, so returned as unavailable. Since no one was really using the IPv6 method of accessing my mail server (it was mostly for testing), removing the AAAA record from DNS cleared up the issue.
Which ISP is the email account with? Comcast, Verizon, Yahoo, Gmail, Hotmail or something else?
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
It is a private e-mail server. The server is configured correctly, as I can receive and send mail from my phone when the phone is connected to wifi. It fails to connect when the phone is using the cellular network.
Also, it has been working previously without change. I first noticed this issue around 1:00pm EDT today (1/10/13).
Your mail service provider may not be recognizing Verizon Wireless as a legitimate access source. Email services block many IP sources to reduce spam. My guess either something changed at your email service provider, their DNS is not working so they cannot determine that Verizon Wireless is legitimate, an IP address changed at Verizon that your provider does not know, or you are roaming on data, or ...... Best place to start and resolve the issue is with your email provider. Have them look at their failure logs if they will.
I turned on logging at the firewall level. I can visit the website on the same server from the phone's browser, and my phone's IP address shows up in the firewall logs as packets are received. When I try to have the phone connect to the mail server, the server gets nothing. It's like verizon's network is not routing the packets to the server at all.
Interesting. Maybe your mail server is on a blacklist (or at least not on the white list) within Verizon. i can understand Verizon and your server not establishing a connection for some reason, but to not try? Maybe your server is not in the DNS name service that Verizon is using. I'm grabbing at straws here.
I understand, and appreciate your efforts to help. The kicker is that it was working fine; I have logs that show successful connections on Jan 4.
I have fixed it from my end.
Seems to have been an issue with IPv6 (AAAA) records in DNS getting mangled. The AAAA record is set to the correct address, but verizon seems to run it through an IPv6 -> IPv4 conversion of some sort. The problem was it wasn't converting it to the correct IPv4 address. Instead, it pointed me to a third party instead. All of the traffic went to this server, which isn't currently running any mail server, so returned as unavailable. Since no one was really using the IPv6 method of accessing my mail server (it was mostly for testing), removing the AAAA record from DNS cleared up the issue.
Great bit of detective work. Glad you got it working.
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