How can I improve the response time of the Telus POP3 server? Unlike the SMTP server, which exhibits delays at each command, the delay with the POP server all seems to be at the front end. After the first connection, the delay disappears, and I had always assumed that delay was due to authentication. But experimentation reveals that part of the delay is due to DNS. Telus uses a Round Robin technique to spread the load between several servers. This is accomplished by setting the TTL (Time To Live) on the DNS lookup for pop.telus.net to 30 seconds. pop.telus.net is a CNAME for pop.svc.telus.net, and imap.telus.net is a CNAME for imap.svc.telus.net. The svc names are not available directly from publicly available DNS servers, but must be obtained via Recursion using the non-svc names. For example, both pop.telus.net & imap.telus.net list
edtnps16.telus.net [198.161.157.116]
clgrps03.telus.net [198.161.156.26]
as authoritative. Choosing either one of those returns pop.svc.telus.net or imap.svc.telus.net with authoratative servers listed as:
clgrgtm00.telus.net [198.161.156.30]
edtngtm00.telus.net [198.161.157.140]
Querying either one of those for the svc name finally yields the result [204.209.205.53] or [199.185.220.248]. Wait 30 seconds between queries and you will get the other answer.
So whatever you are using for DNS servers basically has to go through the same process, which is more than likely causing the response delay. I could load the answers into the HOSTS file, but I don't know how often Telus changes servers.
Edit: I must apologize. I was not using recursion when testing the svc names. Using pop.svc.telus.net & imap.svc.telus.net does improve the response time immensely.
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