Hello,
we had an incorrect exim configuration, which (at least with version
4.30) produces some strange effect. To build a "virus scanning sandwich"
(exim - virus-scanner - exim), a router
virus_route:
driver = manualroute
condition = ${if ! def:header_x-route-via: {yes}}
headers_add = "X-Route-Via: 42-intern"
route_list = * localhost byname
self = send
transport =...
adds a custom header, and other routers (used only when that header
is set) remove it again.
This has been done with
headers_remove = "X-Route-Via:"
though, which is not correct as of the specification.
15. Generic options for routers
states:
headers_remove
[...]
After expansion, the string must consist of a colon-separated list of
header names, not including the terminating colon, for example:
And yes, the terminating colon does make a difference, a very subtle one.
When only one router is involved, it works as intended nevertheless.
The X-Route-Via header is removed when the message leaves exim.
But - if two routers with headers_remove = "X-Route-Via:" are
"passed" (e.g. because of an alias file), the headers stays in
the message..
The behaviour is as intended as soon as the correct form
headers_remove = X-Route-Via
is used.
Maybe that can be fixed ("rule of least surprise").
Greetings,
Lutz
--
_ | Lutz Pressler | Tel: ++49-551-3700002
|_ |\ | | Service Network GmbH | FAX: ++49-551-3700009
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