Any ideas how long gmail cache DNS records ?
In typical "Google knows best" style they appear to be ignoring SOA and TTL and doing their own thing. Changed DNS severs and MX records, other public mail services have picked it up no problem. Gmail however appear to be insisting on continuing to deliver to the old mail servers for god knows how much longer ? Any ideas how long I can expect this to go on for before they Do The Right Thing (TM) ?
Look at it this way, anywhere that has resolvers forwarding to other resolvers that forward to yet another set of resolvers before the query gets to the root servers (anywhere with a complex network and multiple layers of firewalling) will have a succession of caches that need to clear .. so might take somewhat longer than whatever TTL you set. The recommendation therefore is to lower the TTL for a few days BEFORE you change your DNS records. --srs ________________________________ From: NANOG <nanog-bounces+ops.lists=gmail.com@nanog.org> on behalf of Laura Smith via NANOG <nanog@nanog.org> Sent: Saturday, August 10, 2024 7:46:31 PM To: nanog@nanog.org <nanog@nanog.org> Subject: Any ideas how long gmail cache DNS records ? In typical "Google knows best" style they appear to be ignoring SOA and TTL and doing their own thing. Changed DNS severs and MX records, other public mail services have picked it up no problem. Gmail however appear to be insisting on continuing to deliver to the old mail servers for god knows how much longer ? Any ideas how long I can expect this to go on for before they Do The Right Thing (TM) ?
Yawn. Been there, done that. Why do you think the other public mail services have switched over so quickly ? :) This is exclusively a gmail problem. On Saturday, 10 August 2024 at 15:28, Suresh Ramasubramanian <ops.lists@gmail.com> wrote:
Look at it this way, anywhere that has resolvers forwarding to other resolvers that forward to yet another set of resolvers before the query gets to the root servers (anywhere with a complex network and multiple layers of firewalling) will have a succession of caches that need to clear .. so might take somewhat longer than whatever TTL you set. The recommendation therefore is to lower the TTL for a few days BEFORE you change your DNS records.
--srs
From: NANOG <nanog-bounces+ops.lists=gmail.com@nanog.org> on behalf of Laura Smith via NANOG <nanog@nanog.org> Sent: Saturday, August 10, 2024 7:46:31 PM To: nanog@nanog.org <nanog@nanog.org> Subject: Any ideas how long gmail cache DNS records ?
In typical "Google knows best" style they appear to be ignoring SOA and TTL and doing their own thing.
Changed DNS severs and MX records, other public mail services have picked it up no problem.
Gmail however appear to be insisting on continuing to deliver to the old mail servers for god knows how much longer ?
Any ideas how long I can expect this to go on for before they Do The Right Thing (TM) ?
In theory… the number of layers of resolvers shouldn’t increase TTL. Any resolver that gets an answer from an authoritative servers gets the full TTL. A downstream resolver that asks for the records from that server’s cache gets the answers with the TTL appropriately decremented. Any additional layers of resolvers also get the TTL counted down since that initial hit on an authoritative server. But it seems to be common knowledge that layers of resolvers causes things to linger. What is the mechanism? Is it middle caches that are just plain busted and don’t decrement TTL correctly? Something more subtle? On Sat, Aug 10, 2024 at 7:29 AM Suresh Ramasubramanian <ops.lists@gmail.com> wrote:
Look at it this way, anywhere that has resolvers forwarding to other resolvers that forward to yet another set of resolvers before the query gets to the root servers (anywhere with a complex network and multiple layers of firewalling) will have a succession of caches that need to clear .. so might take somewhat longer than whatever TTL you set. The recommendation therefore is to lower the TTL for a few days BEFORE you change your DNS records.
--srs ------------------------------ *From:* NANOG <nanog-bounces+ops.lists=gmail.com@nanog.org> on behalf of Laura Smith via NANOG <nanog@nanog.org> *Sent:* Saturday, August 10, 2024 7:46:31 PM *To:* nanog@nanog.org <nanog@nanog.org> *Subject:* Any ideas how long gmail cache DNS records ?
In typical "Google knows best" style they appear to be ignoring SOA and TTL and doing their own thing.
Changed DNS severs and MX records, other public mail services have picked it up no problem.
Gmail however appear to be insisting on continuing to deliver to the old mail servers for god knows how much longer ?
Any ideas how long I can expect this to go on for before they Do The Right Thing (TM) ?
You might try posting this type of query to the mailop list at https://www.mailop.org/ There's at least one gmail person who responds every now and again over there. (keeping on-list since these kinds of queries come up every now and again and its useful for folks to see the pointer) Matt On 8/10/24 10:16 AM, Laura Smith via NANOG wrote:
In typical "Google knows best" style they appear to be ignoring SOA and TTL and doing their own thing.
Changed DNS severs and MX records, other public mail services have picked it up no problem.
Gmail however appear to be insisting on continuing to deliver to the old mail servers for god knows how much longer ?
Any ideas how long I can expect this to go on for before they Do The Right Thing (TM) ?
On Mon, Aug 12, 2024 at 10:15 AM Matt Corallo <nanog@as397444.net> wrote:
On 8/10/24 10:16 AM, Laura Smith via NANOG wrote:
In typical "Google knows best" style they appear to be ignoring SOA and TTL and doing their own thing.
you MIGHT try just using the 'clear the google-public-dns cache' page: https://developers.google.com/speed/public-dns/cache I think we try really hard to NOT do what you think we're doing...
On Monday, 12 August 2024 at 16:11, Christopher Morrow <morrowc.lists@gmail.com> wrote:
you MIGHT try just using the 'clear the google-public-dns cache' page: https://developers.google.com/speed/public-dns/cache
I think we try really hard to NOT do what you think we're doing...
Thanks Christopher. For the benefit of the list, I received a couple of off-list tip-offs to the link that Chrstopher suggested. I was a bit cynical as I assumed the tool would only have effect on Google's external caches (i.e. 8.8.8.8). The form was failing on Captcha on multiple browsers, which only helped to raise my level of unhappiness with Google. After a bit of searching, I found the same form on another Google page and having plugged the details into the form, caches were indeed cleared both internally and externally at Google and gmails started arriving in the right place. Thanks all for your help on this, both on-list and off-list.
* Laura Smith [Tue 13 Aug 2024, 17:39 CEST]:
For the benefit of the list, I received a couple of off-list tip-offs to the link that Chrstopher suggested.
I was a bit cynical as I assumed the tool would only have effect on Google's external caches (i.e. 8.8.8.8).
The form was failing on Captcha on multiple browsers, which only helped to raise my level of unhappiness with Google.
After a bit of searching, I found the same form on another Google page and having plugged the details into the form, caches were indeed cleared both internally and externally at Google and gmails started arriving in the right place.
For the benefit of the list, was that https://dns.google/cache rather than the previously mentioned https://developers.google.com/speed/public-dns/cache ? --Niels.
For the benefit of the list, was that https://dns.google/cache rather than the previously mentioned https://developers.google.com/speed/public-dns/cache ?
Yes, my bad Niels ! The one you mention is indeed the one that worked, the other one (and the other other one) just captcha's out.
On Tue, Aug 13, 2024 at 11:38 AM Laura Smith <n5d9xq3ti233xiyif2vp@protonmail.ch> wrote:
On Monday, 12 August 2024 at 16:11, Christopher Morrow <morrowc.lists@gmail.com> wrote:
you MIGHT try just using the 'clear the google-public-dns cache' page: https://developers.google.com/speed/public-dns/cache
I think we try really hard to NOT do what you think we're doing...
Thanks Christopher.
(Chris is fine :) sorry for reasons a long time ago my email address ended up as this... naming is hard.)
For the benefit of the list, I received a couple of off-list tip-offs to the link that Chrstopher suggested.
I was a bit cynical as I assumed the tool would only have effect on Google's external caches (i.e. 8.8.8.8).
The form was failing on Captcha on multiple browsers, which only helped to raise my level of unhappiness with Google.
huh, the link I sent was dorked up? (if so I'll see if it is also bad for me and report the breakage)
After a bit of searching, I found the same form on another Google page and having plugged the details into the form, caches were indeed cleared both internally and externally at Google and gmails started arriving in the right place.
excellent! i'm glad it worked.
Thanks all for your help on this, both on-list and off-list.
(from me) Sure thing!
participants (6)
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Christopher Morrow -
Crist Clark -
Laura Smith -
Matt Corallo -
Niels Bakker -
Suresh Ramasubramanian