LTM iRule to direct traffic

You would have to integrate this logic into the existing iRule, if any:

when HTTP_REQUEST {
if { [HTTP::host] eq "domain.com" } {
pool POOL_domain_80
} else {
HTTP::respond 301 Location "https://vip.abc.com"
}
}

POOL_domain_80 has pool members listening on port 80.

Try this:

when HTTP_REQUEST { if { not ([string tolower [HTTP::path]] starts_with "/non-secure-IIS-site") } { HTTP::redirect "https://[HTTP::host][HTTP::uri]" } }

Be sure to have a :80 pool configured behind the port :80 VIP.

Good Luck!

Both of the existing answers make assumptions about your code. It would be helpful if you provided the current iRule as-is or with any necessary substitutions for scrubbing.

Nothing fancy. I'm using the F5 built in irule named _sys_https_redirect when HTTP_REQUEST { HTTP::redirect https://[getfield [HTTP::host] ":" 1][HTTP::uri]

Gotcha. I think that David's answer is likely what you need then. You're going to be replacing the built in rule with a slightly modified version of that default rule to allow the 80 traffic to flow through unaffected