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Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring Multiple Context Mode
Monitoring Security Contexts
Resource Current Peak Limit Denied Context
Syslogs [rate] 1743 2132 N/A
0 Summary
Conns 584 763 280000(S)
0 Summary
Xlates 8526 8966 N/A
0 Summary
Hosts 254 254 N/A
0 Summary
Conns [rate] 270 535 N/A
1704 Summary
Inspects [rate]
270 535 N/A
0 Summary
Other VPN Sessions
0
10
10 740 Summary
Other VPN Burst
0 10
10 730 Summary
S = System: Combined context limits exceed the system limit; the system limit is shown.
The following is sample output from the
show resource usage summary
command, which shows the
limits for 25 contexts. Because the context limit for Telnet and SSH connections is 5 per context, then
the combined limit is 125. The system limit is only 100, so the system limit is shown.
hostname#
show resource usage summary
Resource Current Peak Limit
Denied
Context
Telnet 1 1
100[S]
0
Summary
SSH
2
2
100[S]
0
Summary
Conns 56
90
130000(S)
0
Summary
Hosts 89
102
N/A
0
Summary
S = System: Combined context limits exceed the system limit; the system limit is shown.
The following is sample output from the
show resource usage system
command, which shows the
resource usage for all contexts, but it shows the system limit instead of the combined context limits. The
counter all 0
option is used to show resources that are not currently in use. The Denied statistics indicate
how many times the resource was denied due to the system limit, if available.
hostname#
show resource usage system counter all 0
Resource Current Peak Limit Denied
Context
Telnet 0 0 100 0
System
SSH 0 0 100 0
System
ASDM 0 0 32 0
System
Routes 0 0 N/A 0
System
IPSec 0
0 5 0
System
Syslogs [rate] 1 18 N/A 0
System
Conns 0 1 280000 0
System
Xlates 0 0 N/A 0
System
Hosts 0 2 N/A 0
System
Conns [rate] 1 1 N/A 0
System
Inspects [rate]
0 0 N/A 0
System
Other VPN Sessions
0
10
750
740
System
Other VPN Burst
0 10
750
730
System
Monitoring SYN Attacks in Contexts
The ASA prevents SYN attacks using TCP Intercept. TCP Intercept uses the SYN cookies algorithm to
prevent TCP SYN-flooding attacks. A SYN-flooding attack consists of a series of SYN packets usually
originating from spoofed IP addresses. The constant flood of SYN packets keeps the server SYN queue
full, which prevents it from servicing connection requests. When the embryonic connection threshold of
a connection is crossed, the ASA acts as a proxy for the server and generates a SYN-ACK response to
the client SYN request. When the ASA receives an ACK back from the client, it can then authenticate
the client and allow the connection to the server.
Summary of Contents for 5505 - ASA Firewall Edition Bundle
Page 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Page 61: ...P A R T 1 Getting Started with the ASA ...
Page 62: ......
Page 219: ...P A R T 2 Configuring High Availability and Scalability ...
Page 220: ......
Page 403: ...P A R T 2 Configuring Interfaces ...
Page 404: ......
Page 499: ...P A R T 2 Configuring Basic Settings ...
Page 500: ......
Page 533: ...P A R T 2 Configuring Objects and Access Lists ...
Page 534: ......
Page 601: ...P A R T 2 Configuring IP Routing ...
Page 602: ......
Page 745: ...P A R T 2 Configuring Network Address Translation ...
Page 746: ......
Page 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
Page 846: ......
Page 981: ...P A R T 2 Configuring Access Control ...
Page 982: ......
Page 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
Page 1062: ......
Page 1093: ...P A R T 2 Configuring Application Inspection ...
Page 1094: ......
Page 1191: ...P A R T 2 Configuring Unified Communications ...
Page 1192: ......
Page 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
Page 1334: ......
Page 1379: ...P A R T 2 Configuring Advanced Network Protection ...
Page 1380: ......
Page 1475: ...P A R T 2 Configuring Modules ...
Page 1476: ......
Page 1549: ...P A R T 2 Configuring VPN ...
Page 1550: ......
Page 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
Page 1966: ......
Page 2059: ...P A R T 2 System Administration ...
Page 2060: ......
Page 2098: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Troubleshooting Viewing the Coredump ...
Page 2099: ...P A R T 2 Reference ...
Page 2100: ......