Home Theater Server User Manual
Table Of Contents
- Contents
- About This Document
- Network Security
- TCP SYN attacks
- IP TCP syn-proxy
- Granular application of syn-proxy feature
- Syn-def
- No response to non-SYN first packet of a TCP flow
- Prioritizing management traffic
- Peak BP utilization with TRAP
- Transaction Rate Limit (TRL)
- Understanding transaction rate limit
- Configuring transaction rate limit
- Configuring the maximum number of rules
- Saving a TRL configuration
- Transaction rate limit command reference
- Global TRL
- TRL plus security ACL-ID
- security acl-id
- Transaction rate limit hold-down value
- Displaying TRL rules statistics
- Displaying TRL rules in a policy
- Displaying IP address with held down traffic
- Refusing new connections from a specified IP address
- HTTP TRL
- Overview of HTTP TRL
- Configuring HTTP TRL
- Displaying HTTP TRL
- Display all HTTP TRL policies
- Display HTTP TRL policy from index
- Display HTTP TRL policy client
- Display HTTP TRL policy starting from index
- Display HTTP TRL policy matching a regular expression
- Display HTTP TRL policy client index (MP)
- Display HTTP TRL policy client index (BP)
- Display HTTP TRL policy for all client entries (BP)
- Downloading an HTTP TRL policy through TFTP
- HTTP TRL policy commands
- Logging for DoS Attacks
- Maximum connections
- clear statistics dos-attack
- Maximum concurrent connection limit per client
- Firewall load balancing enhancements
- Syn-cookie threshhold trap
- Service port attack protection in hardware
- Traffic segmentation
- DNS attack protection
- Access Control List
- How ServerIron processes ACLs
- Default ACL action
- Types of IP ACLs
- ACL IDs and entries
- ACL entries and the Layer 4 CAM
- Configuring numbered and named ACLs
- Modifying ACLs
- Displaying a list of ACL entries
- Applying an ACLs to interfaces
- ACL logging
- Dropping all fragments that exactly match a flow-based ACL
- Enabling ACL filtering of fragmented packets
- Enabling hardware filtering for packets denied by flow-based ACLs
- Enabling strict TCP or UDP mode for flow-based ACLs
- ACLs and ICMP
- Using ACLs and NAT on the same interface (flow-based ACLs)
- Displaying ACL bindings
- Troubleshooting rule-based ACLs
- IPv6 Access Control Lists
- Network Address Translation
- Syn-Proxy and DoS Protection
- Understanding Syn-Proxy
- Configuring Syn-Proxy
- DDoS protection
- Configuring a security filter
- Configuring a Generic Rule
- Configuring a rule for common attack types
- Configuring a rule for ip-option attack types
- Configuring a rule for icmp-type options
- Configuring a rule for IPv6 ICMP types
- Configuring a rule for IPv6 ext header types
- Binding the filter to an interface
- Clearing DOS attack statistics
- Clearing all DDOS Filter & Attack Counters
- Logging for DoS attacks
- Displaying security filter statistics
- Address-sweep and port-scan logging
- Secure Socket Layer (SSL) Acceleration
- SSL overview
- SSL acceleration on the ServerIron ADX
- Configuring SSL on a ServerIron ADX
- Basic SSL profile configuration
- Advanced SSL profile configuration
- Configuring Real and Virtual Servers for SSL Termination and Proxy Mode
- Configuration Examples for SSL Termination and Proxy Modes
- SSL debug and troubleshooting commands
- Displaying socket information
ServerIron ADX Security Guide 115
53-1002440-03
Configuring Syn-Proxy
5
ServerIronADX(config)# interface ethernet 2/1
ServerIronADX(config-if-e1000-2/1)# ip tcp syn-proxy in
Syntax: interface ethernet <slot number/port number>
Syntax: ip tcp syn-proxy in
The ip tcp syn-proxy command can be configured for either a physical interface (as shown) or a
ve interface.
Setting Attack-Rate-Threshold
A DoS attack threshold specifies the number of SYNs, without corresponding ACKs, the ServerIron
ADX accepts before writing a warning message to the system log (every 60 seconds for the duration
of the attack).
To configure a threshold value for the SYN attack rate, use the following command:
ServerIronADX(config)# server syn-cookie-attack-rate-threshold 2000
Syntax: server syn-cookie-attack-rate-threshold <threshold value>
<threshold value> is a number between 1 and 10,000,000. The default is 1000.
NOTE
If you do not configure a threshold, the ServerIron ADX does not write SYN attack messages to the
log file.
If the number of SYNs (without corresponding ACKs), received on the ServerIron ADX exceeds the
specified threshold of 2000, the ServerIron ADX writes the following message to the log file every
60 seconds for the duration of the attack:
"CRITICAL: syn-cookie attack rate 2005 exceeds attack rate threshold 2000"
Setting SYN-Ack-Window-Size
To globally set the TCP window size that the ServerIron ADX uses on a SYN-ACK packet sent back to
a client with SYN-Cookie, use the following command:
ServerIronADX(config)# server syn-proxy-syn-ack-window-size 5000
Syntax: [no] server syn-proxy-syn-ack-window-size <value>
<value> is the window size. The range from 1 to 65536. The default is 8192.
This command works with a syn-proxy configuration. By having syn-ack-window-size configured, the
window size of the SYN-ACK packet sent from ServerIron ADX to client will have the configured
<value>.
This feature can be used to prevent the client from sending HTTP-Gets before the server side 3-way
handshake is established.
Setting Reset-Using-Client-MAC
NOTE
In this rare corner-case, the reset-using-client-mac command is needed to send a reset to the client.
To globally send a Reset to the client using the client MAC address on the interfaces where
Syn-Proxy is enabled, use the following command: