EPM won't allow Custom extensions with the same number as locals

I filed a support request, but whilst they’re working on it I thought I’d see if anyone has a workaround.

I have an extension mapped (510) onto my Snom 320. I want to add a new Custom Extension (510 @ However, I am unable to do so. I can successfully map a new custom extension if I define 511 @, however the old system requires 510 and I don’t want users to have to renumber during the migration to the new server…

Actually, it matters not whether or not the local extension has been mapped. Mapping the custom extension always maps a local one if the left part of the SIP address is the same.

Is there a way around this?

OK, I have developed a workaround. Not ideal but it allows us to continue

The custom extensions are defined as zXXX instead of XXX (so my custom extension will be defined as z510 not 510). Mapping proceeds as normal.

Then define a cronjob to run each minute
code for the job is


for f in $FILES
sed -i -r “s/z([0-9][0-9][0-9])/\1/g” $f

Works for me. It’s a bit of a bodge but allows the Endpoint Manager to be used.


Its already being looked into and should be fixed in the next release to allow the same extension number to be defined as a custom extension that exist on the local system already.