Tagipv6

September 9, 2016

Ask Laura: Should I let my ESP give me a shared IP?

By laura
4 Min read
5 comments
09September

Dear Laura, Our company has been shopping around for ESPs and most of them want to put us on a shared IP address. I have always heard that senders should get dedicated IPs. Will this hurt our deliverability? Regards, Sharing is Hard Dear Sharing, For a long time, IP reputation was the major factor in identifying good mail from bad mail. Good IPs helped mail get into the inbox. Poor IPs were...

June 9, 2016

Gmail / Apps authentication issues

By steve
1 Min read
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09June

I’ve seen several reports of unexpected rejections for unauthenticated email to Google over IPv6 today. Unauthenticated mail over IPv6 is a bad idea, but Google usually spam folders it rather than rejecting it. The Gmail status dashboard is reporting an issue “Some messages sent to consumer Gmail accounts are being rejected due to authentication enforcement” so something...

October 7, 2015

IPv6 and authentication

By steve
2 Min read
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07October

I just saw a post over on the mailop mailing list where someone had been bitten by some of the IPv6 email issues I discussed a couple of months ago. They have dual-stack smarthosts – meaning that their smarthosts have both IPv4 and IPv6 addresses, and will choose one or the other to send mail over. Some domains they send to use Office 365 and opted-in to receiving mail over IPv6, so their...

July 29, 2015

IPv6 Email is a little different

By steve
5 Min read
7 comments
29July

On Monday I talked about how big IPv6 address space is, and how many IPv6 addresses will be available to end users. We’re mostly an email blog, though, so what’s the relevance to sending email? If the recipient you’re sending to has an IPv6 mailserver you can send mail to them over IPv6, if you choose to. If they only have an IPv6 mailserver, with no IPv4 mailserver at all then...

July 27, 2015

IPv6 is big

By steve
4 Min read
5 comments
27July

IPv6 is big. Really big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to IPv6. The old Internet, the one you’re probably using right now, runs on IP version 4. IPv4 addresses have numbers and dots; they look like 172.224.4.56. There are about 4,009,754,624...

April 24, 2015

Office365/EOP IPv6 changes starting today

By josh
2 Min read
1 comment
24April

Terry Zink at Microsoft posted earlier this week that Office365/Exchange Online Protection will have a significant change this week. Office365 uses Exchange Online Protection (EOP) for spam filtering and email protection. One of the requirements to send to EOP over IPv6 is to have the email authenticated with either SPF or DKIM.  If the mail sent to Office365/EOP over IPv6 is not authenticated...

July 11, 2013

The death of IP based reputation

By laura
3 Min read
13 comments
11July

Back in the dark ages of email delivery the only thing that really mattered to get your email into the inbox was having a good IP reputation. If your IP sent good mail most of the time, then that mail got into the inbox and all was well with the world. All that mattered was that good IP reputation. Even better for the people who wanted to game the system and get their spam into the inbox, there...

June 6, 2012

World IPv6 launch day

By laura
1 Min read
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06June

Today is world IPv6 launch day. A group of ISPs, network hardware manufacturers and web companies permanently enabled IPv6 for their products and services. What’s this got to do with email? According to a post on the NANOG mailing list the very first email to arrive at the Comcast IPv6 mailserver was received a minute after the server was turned on. This email was spam and was caught by...

January 31, 2011

Yes, we have no IP addresses, we have no addresses today

By steve
4 Min read
4 comments
31January

We’ve just about run out of the Internet equivalent of a natural resource – IP addresses. ICANN allocated the last couple of blocks of general usage IPv4 addresses to APNIC earlier today. There are just five usable blocks of addresses left, and they’re reserved by IANA policy for the final phase of IPv4 exhaustion, one for each RIR. Like any other resource that’s been...

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