Leaving open High-number ports

Murdock1979 · 11-19-2007, 07:19 AM

Hello!

I am wondering about the security concerns of leaving open high-number ports (like way above the 1023, say 9,000+). Many applications, such as bittorrents and xmms, use high ports randomly, which makes it necessary to always open closed ports, unless the higher numbers are always left opened.

Thanks!
Murdock

nomb · 11-19-2007, 09:15 AM

I don't know which client you use but most bittorent clients allow you to set static ports if you so choose. If someone does a scan and finds the high ports open then it could be possible for them to figure out which service is running on them and exploit/use them.

Murdock1979 · 11-19-2007, 10:52 AM

Thanks for the quick reply!

I don't just use bitorrents, but also there are other services being used. For example, SIP phones use higher numbered port numbers for the RTP channel.

Would it be a problem if there are no services running on that port?

Thanks,
Murdock