anonymous fax calls inbound

[eddchen]

Hi guys,

We have a client reporting that he is receiving numerous fax calls every now and then, we got him to diver the call to a fax machine and trying to get the sending number and it is keep changing or sometimes come up with a dummy one like 123454321

We have tried publish his number as the DO NOT CALL/FAX number in the national database which suppose to block the marketing companies to send fax or calls to you for marketing reason, but that didn't help.

Any idea how to tackle this?

Thanks.

Ed

[eddchen]

No one from cisco can shed a light or point  a direction for this issue??

[Wayne DeNardi]

Hi Ed,

You'll need to provide some more details on the systems being used to give us a better understanding of where you're seeing the issue, what systems you're using, what protocols your equipment are talking, and anythign else you can think that might lead us to the source of your problem.

At a quick guess, it sounds like there's a SIP connection somewhere there and you're getting probed by a SIP scanner such as SIPVicious.

Wayne
--
Please remember to rate responses and to mark your question as answered if appropriate.

[eddchen]

HI Wayne,

Thanks for the reply. It is more a general question, we are using cucm 8.6, 794/6x phones. indial range is coming from ISDN E1 links to service provider. Gateway is MGCP, and phones are SCCP phones. The in dial number range is attached to 4 E1 links for incoming and outgoing, but only some numbers are affected at the moment(like for the last 6 months).

For example, we have a 4 thousand range on 4 E1 links. 9999 2/3/4/5xxx, only 9999 4 xxx is affected, even though all the 4 thousand range numbers a re sharing the same in coming out going E1 links.

CUCM don't think it can do anything to block it.....Gateway maybe, but since the sourcing number is keep changing or fake, doubt if there is mechanism can be useful on the Gateway to tacket this. Anyone with similar experience with this and any proposed fix?

Regards,

Ed

[Wayne DeNardi]

From that description, I don't think it's likely you can do too much.

Your best bet would be to contact your E1 provider and to see if they can do a trace and/or block on the nuisance calls.

Wayne
--
Please remember to rate responses and to mark your question as answered if appropriate.