We are using NIDS - 4250 for the last 15 months.We are continuously monitoring its disk & memory usage. We found from starting the memory usage is increasing normally & gradually(1% in 40-50 days). But for the past two months we are finding the mem usage is increasing at a faster rate (1% in 3-4 days). At present the mem usage is 84%. Please tell us why this is happening? & How to reduce this memory usage?
Check whether the ammount of missed packets are also increasing 'show interfaces FastEthernet?/?'. If this is the case then your IPS might be increasingly overloaded. Please be aware that a 4250 can analyse up to 350 Mbps .. then it will start dropping packets and performance will decrease. Also you can check your signatures and retire the ones that you consider irrelevant for your scenario. This will remove the signature from the signature Engines and will inprove sensor performance. This can also be done for sigantures that might be firing up too many false positives alerts.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...