text_combined: marc perkel vrvaperkelcom let clarify something using bogus mx records lets assume following bogus0domaincom mx 10 realdomaincom mx 20 backupdomaincom mx 30 bogus1domaincom mx 40 bogus2domaincom mx 50 host bogus1 bogus2 100 safe effective bogus ips dead port 25 return 421 let retry 421 let log hits want see working bogus low end trickier firewall port 25 almost everyone cant 421 error breaks qmail servers qmail wont retry higher numbered mx records seeing 421 try port closed occasionally server something weird might open port 25 one specific ip running something really dumb think ive twice open port 25 problem user solved problem part mx sandwich youll get rid 80 spam lose good email fearful going way higher numbered mx leave bottom thu 07 aug 2008 030003 0800 ot bogus mx opinions