Just found out from some of my clients that ISP's are now starting blocking email ports from other hosts that are not the ISP's domains. Ports that are being blocked are SMTP Ports: 25, 587, Not sure about 465 POP3 Ports: 110, 995 IMAP Ports: 143, 993 SMTP is easy get around this issue in WHM. But how about POP3 and IMAP ports? Centrylink was bought out by Quest so they are blocking ports from above. About 30% of my clients are having issues in get their email.