@startuml rectangle "John" as U1 rectangle "MUA 1" as MUA1 rectangle "MSA 1" as MSA1 rectangle "MTA 1" as MTA1 rectangle "DNS" as DNS rectangle "MTA 2" as MTA2 rectangle "MDA 2" as MDA2 rectangle "Mailbox 2" as MB2 rectangle "MRA 2" as MRA2 rectangle "MUA 2" as MUA2 rectangle "Kate" as U2 U1 -right-> MUA1 MUA1 -right-> MSA1 : SMTP (587) MSA1 -right-> MTA1 DNS -left-> MTA1 MTA1 -right-> DNS MTA1 -down-> MTA2 : " SMTP (25)" MTA2 -right-> MDA2 MDA2 -down-> MB2 MB2 -left-> MRA2 MRA2 -left-> MUA2 : IMAP / POP3 MUA2 -left-> U2 @enduml Submit amiga aws-orange black-knight bluegray blueprint cerulean-outline cerulean crt-amber crt-green cyborg-outline cyborg hacker lightgray mars materia-outline materia metal mimeograph minty plain reddress-darkblue reddress-darkgreen reddress-darkorange reddress-darkred reddress-lightblue reddress-lightgreen reddress-lightorange reddress-lightred sandstone silver sketchy-outline sketchy spacelab spacelab-white superhero-outline superhero toy united vibrant       🎉 Discover the future PlantUML Web Editor! 🚀  PNG  SVG  ASCII Art