{"id":1544,"date":"2015-09-09T12:55:21","date_gmt":"2015-09-09T04:55:21","guid":{"rendered":"http:\/\/www.computersolutions.cn\/blog\/?p=1544"},"modified":"2015-09-09T12:55:21","modified_gmt":"2015-09-09T04:55:21","slug":"google-mail-issues-from-china-again","status":"publish","type":"post","link":"https:\/\/www.computersolutions.cn\/blog\/2015\/09\/google-mail-issues-from-china-again\/","title":{"rendered":"Google mail issues from China (again)"},"content":{"rendered":"

Some of our clients are experiencing delivery issues to some domains that use Gmail\/Google for their email.<\/p>\n

I previously covered that here – http:\/\/www.computersolutions.cn\/blog\/2015\/04\/gmail-and-other-google-hosted-mail-delivery-issues\/<\/a><\/p>\n

The issue is that China is still blocking Gmail\/ Google hosted mail, and the recipient domain hasn’t setup their MX records correctly. <\/p>\n

This is fine for servers outside of China, where all of googles mail servers (should) work, but breaks things for those inside China, where only a few servers are reachable.<\/p>\n

Google hosted mail settings are here: https:\/\/support.google.com\/a\/answer\/33915?hl=en<\/a><\/p>\n

You’ll note that there are 5 different email servers that are listed in priority order.<\/p>\n

Priority\tMail Server
\n1\tASPMX.L.GOOGLE.COM.
\n5\tALT1.ASPMX.L.GOOGLE.COM.
\n5\tALT2.ASPMX.L.GOOGLE.COM.
\n10\tALT3.ASPMX.L.GOOGLE.COM.
\n10\tALT4.ASPMX.L.GOOGLE.COM.<\/code><\/p>\n

For mail servers, the higher number is more important, so a priority of 1 will be the first server tried, then the next highest number, and so on.<\/p>\n

If I try to connect to the servers from China.<\/p>\n

telnet ASPMX.L.GOOGLE.COM 25
\nTrying 74.125.200.27…
\n(times out)<\/em><\/p>\n

telnet ALT1.ASPMX.L.GOOGLE.COM 25
\nTrying 173.194.72.26…
\n(times out)<\/em><\/p>\n

telnet ALT2.ASPMX.L.GOOGLE.COM 25
\nTrying 74.125.25.26…
\n(times out)<\/em><\/p>\n

telnet ALT3.ASPMX.L.GOOGLE.COM 25
\nTrying 64.233.169.26…
\nConnected to ALT3.ASPMX.L.GOOGLE.COM.
\nEscape character is ‘^]’.
\n(yay, we have a winner!)<\/em><\/p>\n

telnet ALT4.ASPMX.L.GOOGLE.COM 25
\nTrying 74.125.70.27…
\nConnected to ALT4.ASPMX.L.GOOGLE.COM.
\nEscape character is ‘^]’.
\n(yay, we have a winner!)<\/em><\/p>\n

So, we can see that alt3, alt4 work, but none of the others do (as of 9th September 2015 from Shanghai)<\/p>\n

So, some rudimentary testing shows that some servers work, and some do not.
\nHow does that apply to real world examples.<\/p>\n

Lets look at a non-working domain – ihg.com<\/p>\n

dig mx ihg.com<\/p>\n

;; ANSWER SECTION:
\nihg.com.\t\t600\tIN\tMX\t100 aspmx3.googlemail.com.
\nihg.com.\t\t600\tIN\tMX\t50 alt1.aspmx.l.google.com.
\nihg.com.\t\t600\tIN\tMX\t50 alt2.aspmx.l.google.com.
\nihg.com.\t\t600\tIN\tMX\t100 aspmx2.googlemail.com.
\nihg.com.\t\t600\tIN\tMX\t10 aspmx.l.google.com.<\/code><\/p>\n

You should easily be able to see 2 things.
\n1 – that the MX records are not as per Google settings.
\n2 – that the 2 working MX records are not listed.<\/p>\n

This means that while their MX records probably work oversea’s, they will not be deliverable from China. They need to amend their MX records to Googles recommended settings.<\/p>\n

Lets look at another example.<\/p>\n

dig mx rsms-west.com<\/p>\n

;; ANSWER SECTION:
\nrsms-west.com.\t\t6238\tIN\tMX\t30 alt2.aspmx.l.google.com.
\nrsms-west.com.\t\t6238\tIN\tMX\t10 aspmx.l.google.com.
\nrsms-west.com.\t\t6238\tIN\tMX\t40 aspmx2.googlemail.com.
\nrsms-west.com.\t\t6238\tIN\tMX\t50 aspmx3.googlemail.com.
\nrsms-west.com.\t\t6238\tIN\tMX\t20 alt1.aspmx.l.google.com.<\/code><\/p>\n

Once again, we can see that the alt3, and alt4 servers are missing, and unfortunately none of the other listed servers are connectable from China.<\/p>\n

Lastly, lets look at a working server<\/p>\n

dig mx teamsequel.com<\/p>\n

teamsequel.com.\t\t12878\tIN\tMX\t1 ASPMX.L.GOOGLE.com.
\nteamsequel.com.\t\t12878\tIN\tMX\t5 ALT1.ASPMX.L.GOOGLE.com.
\nteamsequel.com.\t\t12878\tIN\tMX\t5 ALT2.ASPMX.L.GOOGLE.com.
\nteamsequel.com.\t\t12878\tIN\tMX\t10 ALT3.ASPMX.L.GOOGLE.com.
\nteamsequel.com.\t\t12878\tIN\tMX\t10 ALT4.ASPMX.L.GOOGLE.com.<\/code><\/p>\n

You can see that they have the correct Gmail settings as per Gmail \/ Google settings page, and mail to them is deliverable (as alt3, alt4 are currently not being blocked by the beneficent government of China).<\/p>\n

Unfortunately as this is an issue that is out of our control (MX records are incorrect, and China is being difficult), we cannot mitigate against it. The affected domains will need to amend their MX records appropriately as per the page here- https:\/\/support.google.com\/a\/answer\/33915?hl=en<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

Some of our clients are experiencing delivery issues to some domains that use Gmail\/Google for their email. I previously covered that here – http:\/\/www.computersolutions.cn\/blog\/2015\/04\/gmail-and-other-google-hosted-mail-delivery-issues\/ The issue is that China is still blocking Gmail\/ Google hosted mail, and the recipient domain hasn’t setup their MX records correctly. This is fine for servers outside of China, where […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[73,111,25],"tags":[514,87,516,515,218,509,11,532],"class_list":["post-1544","post","type-post","status-publish","format-standard","hentry","category-email","category-government","category-technical-mumbo-jumbo","tag-blocking","tag-china","tag-delivery-issues","tag-email-issues","tag-firewall","tag-gmail","tag-google","tag-government"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/posts\/1544","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/comments?post=1544"}],"version-history":[{"count":1,"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/posts\/1544\/revisions"}],"predecessor-version":[{"id":1545,"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/posts\/1544\/revisions\/1545"}],"wp:attachment":[{"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/media?parent=1544"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/categories?post=1544"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.computersolutions.cn\/blog\/wp-json\/wp\/v2\/tags?post=1544"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}