Single field substitutions extract a single subdomain part from the host/domain specification being rewritten. The available single field substitutions are shown in Table 11–6.
Table 11–6 Single Field Substitutions
Control Sequence |
Usage |
---|---|
$&n |
Substitute the nth element, n=0,1,2,..,9, in the host specification (the part that did not match or matched a wildcard of some kind). Elements are separated by dots; the first element on the left is element zero. The rewrite fails if the requested element does not exist. |
$!n |
Substitute the nth element, n=0,1,2,..,9, in the host specification (the part that did not match or matched a wildcard of some kind). Elements are separated by dots; the first element on the right is element zero. The rewrite fails if the requested element does not exist. |
$*n |
Substitute the nth element, n=0,1,2,...,9, in the domain specification (the part that did match explicit text in the pattern). Elements are separated by dots; the first element on the left is element zero. The rewrite fails if the requested element does not exist. |
$#n |
Substitute the nth element, n=0,1,2,...,9, in the domain specification (the part that did match explicit text in the pattern). Elements are separated by dots; the first element on the right is element zero. The rewrite fails if the requested element does not exist. |
Suppose the address jdoe@eng.siroe.com matches the following rewrite rule:
*.SIROE.COM $U%$&0.siroe.com@mailhub.siroe.com
Then the result from the template will be jdoe@eng.siroe.com with mailhub.siroe.com used as the routing system.