{"id":16878,"date":"2012-11-25T11:14:00","date_gmt":"2012-11-25T16:14:00","guid":{"rendered":"https:\/\/nuxx.net\/blog\/?p=16878"},"modified":"2012-11-25T11:14:15","modified_gmt":"2012-11-25T16:14:15","slug":"how-to-disable-ipv6-w-sendmail-on-freebsd-9-0-release","status":"publish","type":"post","link":"https:\/\/nuxx.net\/blog\/2012\/11\/25\/how-to-disable-ipv6-w-sendmail-on-freebsd-9-0-release\/","title":{"rendered":"How To Disable IPv6 w\/ Sendmail on FreeBSD 9.0-RELEASE"},"content":{"rendered":"

Due to some issues with Comcast flagging some email I’ve been sending via IPv6<\/a> as Spam I wanted to keep mail from being sent this way. Comcast publishes this document<\/a> explaining how to keep IPv6 mail from being blocked, but I’ve got some rDNS issues to sort out before I can work through all of those. So, in the mean time I simply wanted to stop<\/p>\n

It took a bit to figure out how to disable IPv6 in the base Sendmail, but now that I’ve got it done I figured I’d share. This is in 9.0-RELEASE<\/a>, but I’m sure it applies to many other recent FreeBSD Versions:<\/p>\n

Edit \/etc\/make.conf<\/tt> to ensure that IPv6 is turned off for Sendmail compiles. Add this line to the file:
\n<\/tt><\/p>\n

SENDMAIL_CFLAGS= -UNETINET6<\/tt><\/p>\n

Rebuild Sendmail as described here in the FreeBSD Handbook<\/a>:<\/p>\n

# cd \/usr\/src\/lib\/libsmutil<\/tt>
\n# make cleandir && make obj && make<\/tt>
\n# cd \/usr\/src\/lib\/libsm<\/tt>
\n# make cleandir && make obj && make<\/tt>
\n# cd \/usr\/src\/usr.sbin\/sendmail<\/tt>
\n# make cleandir && make obj && make && make install<\/tt><\/p>\n

Then, go into your Sendmail config directory (\/etc\/mail<\/tt>), and if you haven’t so before, run make all to build your machine-specific Sendmail config files.<\/p>\n

Edit hostname.mc<\/tt> and locate the line that reads DAEMON_OPTIONS(`Name=IPv6, Family=inet6, Modifiers=O')<\/tt> and comment it out by adding a dnl in front of it:<\/p>\n

dnl DAEMON_OPTIONS(`Name=IPv6, Family=inet6, Modifiers=O')<\/tt><\/p>\n

Compile the Sendmail config and restart Sendmail:<\/p>\n

make install<\/tt>
\nmake restart<\/tt><\/p>\n

And, now you’re done! Look at \/var\/log\/maillog<\/tt> to ensure that mail is no longer being delivered via IPv6.<\/p>\n","protected":false},"excerpt":{"rendered":"

Due to some issues with Comcast flagging some email I’ve been sending via IPv6 as Spam I wanted to keep mail from being sent this…<\/p>\n

Continue readingHow To Disable IPv6 w\/ Sendmail on FreeBSD 9.0-RELEASE<\/span><\/a><\/div>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,4],"tags":[],"class_list":["post-16878","post","type-post","status-publish","format-standard","hentry","category-computers","category-nuxxnet","entry"],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/16878","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/comments?post=16878"}],"version-history":[{"count":4,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/16878\/revisions"}],"predecessor-version":[{"id":16882,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/posts\/16878\/revisions\/16882"}],"wp:attachment":[{"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/media?parent=16878"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/categories?post=16878"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nuxx.net\/blog\/wp-json\/wp\/v2\/tags?post=16878"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}