I got a customer with system i didn't install that had a lot of problems including listing in RBLs, performance problems, connectors problems and more.
I already solved most of the problems and my current (and hopefully the last one) is the usage of POP and SMTP accounts using this server.
In the office I don't have any problems sending and receiving as all clients are using outlook connected to the exchange.
Problem is with the external users using POP and SMTP.
checking with nslookup form the server, client in the office or external client I get the same results:
primary name server = ns1.dnsexit.com
responsible mail addr = admin.netdorm.com
serial = 2000060701
refresh = 14400 (4 hours)
retry = 2400 (40 mins)
expire = 604800 (7 days)
default TTL = 1200 (20 mins)
sybilgroup.com nameserver = ns3.dnsexit.com
sybilgroup.com nameserver = ns4.dnsexit.com
sybilgroup.com nameserver = ns1.dnsexit.com
sybilgroup.com nameserver = ns2.dnsexit.com
sybilgroup.com MX preference = 5, mail exchanger = mail.sybilgroup.com
sybilgroup.com MX preference = 5, mail exchanger = sybilgroup.com
sybilgroup.com internet address = 18.104.22.168
I configured an outlook account with POP and SMTP = sybilgroup.com.
SMTP requires authentication is check.
POP3 is working and external users can get emails but not send.
when performing test send i get popup for username and password.
what I'm missing? something in the exchange settings? or maybe the DNS settings?