Description of problem: SIGPIPE on older kernel versions when sending mail. Version-Release number of selected component (if applicable): exim-4.93-2.el7.x86_64 How reproducible: Steps to Reproduce: 1. Update Exim using EPEL 7 repository. Version must be Exim-4.93-2.el7.x86_64 2. Send mail. In function sendto will be error SIGPIPE. Actual results: Mail not sent Expected results: Mail must be sent Additional info: This is because parameter hosts_try_fastopen is disabled. Please include patch: https://bugs.exim.org/show_bug.cgi?id=2518 To work where there is no support FAST_OPEN or support is disabled. And kept backward compatible.