Forum Discussion

mframpton_60606's avatar
mframpton_60606
Icon for Nimbostratus rankNimbostratus
Oct 23, 2008

Unused ports respond to port scan

We're in the process of nailing down open ports on our network. We've found that if we do a port scan on an LTM VIP with a defined port, all the unused ports will responded with an ACK then Reset, wh...
config
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hooleylist's avatar
hooleylist
Icon for Cirrostratus rankCirrostratus
Oct 27, 2008
I'm pretty sure TCP RFCs dictate that LTM or any host send an ACK of the previous packet and a RST if the port isn't in a listening state. I'm not sure if this is configurable within the internal database. I didn't see any keys which looked related in a quick search of the database (b db list|less -i).

 

 

You could potentially define packet filters (Click here) to drop packets to undefined ports. That would probably get fairly tedious to configure though. Or you could do this on an upstream firewall.

 

 

Aaron