Possible issue with an iRule

If you're seeing connection resets with an iRule, check the /var/log/ltm file for runtime TCL errors.

However, as Nitass said, you should be able to rework this iRule with string pattern matching to avoid the high CPU costs of regexes. I'm not exactly sure what logic you're trying to implement, but here's a stab at it:

when HTTP_REQUEST {
 Remove www. from the host header value if it is present
set host [string map {www. ""} [string tolower [HTTP::host]]]
log local0. "[IP::client_addr]:[TCP::client_port]: Parsed $host from [HTTP::host]"

switch $host {
"domain" -
"wsecure" -
"ssl" {
log local0. "[IP::client_addr]:[TCP::client_port]: Matched part of $host, redirecting"
HTTP::redirect "https://www.domain.com/MS/RedirectMS?site=hub&value=$host"
}
}
}

http://devcentral.f5.com/wiki/iRules.switch.ashx

http://devcentral.f5.com/wiki/iRules.getfield.ashx

Aaron