Allied Telesis Layer 3 Switches manuale d’uso

C613-16103-00 REV A www .alliedtelesis.com How T o | Intr oduction Allied T elesis switches include a range of sophisti cated security features at la y er 2 and la yer 3. This How T o Note des cribes these featur es and includes brief examples of ho w to configure them. The implementations shown in this Ho w T o Note should be thought of as industr[...]

Which pr oducts and software v ersions does this information apply to? Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 2 Appendix: Configuration scripts for MA C-for ced forwarding example ... ................................ 27 Edge switch 1 ............... ............................ ........................... .........[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 3 Securing the de vice Securing the de vice The first step towar ds making a secur e network is to secur e the netw orking equipment itself. There ar e two aspects to this. Firstly , ph ysical security is vital—lock your netw orking equ ipment a wa y . Secondly , straight af[...]

Pr otecting the network Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 4 Ser vice pro viders need to pre vent storms fr om disrupting ser vices to customers. AlliedW are offe rs t he fo llow ing op ti ons for m iti gat in g st orm s: z limiting broadcasts and m ulticasts on a por t ( “Bandwidth limiting” on page 4 ) z [...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 5 Pr otecting the network Using QoS policy-based storm pr otection P olicy-based storm protection lets y ou specify one of a range of actions for the s witch to take when it detects a br oadcast storm. It is a par t of the QoS functionality . P olicy-based storm protection is [...]

Pr otecting the network Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 6 Example The following example applie s storm protection to classified br oadcast traffic on por t 1 . If there is a storm, it tak es the link down f or 60 seconds. set switch enhancedmode=qoscounters Reboot after turning on enhanced mode. create class[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 7 Pr otecting the network 2. Set the sensitivity in detecting rapid MA C mo vement, by using the f ollowing command to tell the switch how many times a MA C addr ess can move ports in one second: set switch thrashlimit=5..255 Configuration on trunk groups Rapid MA C movement p[...]

Pr otecting the network Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 8 IGMP filtering IGMP filtering lets you dictate exac tly which multicast gr oups a spec ific port can receiv e , by cr eating a fil ter list and applying it to the port. Differ ent por ts ma y ha ve diff erent filter lists applied to them. If desire d,[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 9 Managing the de vice securel y Mana ging the de vice securel y In Ethernet and br oadc ast netw orks the pri vacy of traffic is not g uaranteed. Hubs and networks outside the administrator's contr ol ma y leak sensitive data to unwanted r ecipients. A hack er ma y even [...]

Managing the de vice securel y Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 10 Using SSL for secur e w eb access If you pr efer to configur e the switch using the conv enient we b-based GUI, then this is un encr ypted by default. SSL lets y ou use the GUI securely , by using HTTPS instead of HTTP . 1. Add a security offi[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 11 Managing the de vice securel y Examples T o allow the user “ste ve” full r ead, write and notify SNMP access to the switch: enable snmp add snmp view=full oid=1.3.6.1 type=include add snmp group=super-users securitylevel=authPriv readview=full writeview=full notifyview=[...]

Managing the de vice securel y Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 12 Whitelisting telnet hosts For an y remote management of a netw ork de vice, Allied T elesis recommends y ou use SSH, Secure HTTP ( SSL), or SNMPv3. Theref ore, we recommend y ou block all telnet access to the switch by disabling the telnet ser[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 13 Managing the de vice securel y Building a whitelist thr ough QoS On A T -8948, A T -9900, A T -990 0s, and x900 Series switches, use classifiers to build a whitelist and QoS to apply it. 1. Create classifiers to mat ch telnet traffic fr om permitted IP addr esses to the swi[...]

Identifying the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 14 Identifying the user This section describes methods for authorising and tracking users and pre venting them fr om changing their identi ty on the netw ork. IP spoofing and tracking Unknown users who attempt to change IP ad dres s—to cir cumvent billin[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 15 Identifying the user Rejecting Gratuitous ARP (GARP) Hosts can use GARP to anno unce th eir presence on a subnet. It is a helpfu l mechanism, par ticularly when ther e is a chance of duplicate addresses. Ho wev er , attack ers can use GARP to penetrate the networ k b y addi[...]

Identifying the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 16 For mor e information about setting up DHCP snooping, see How T o Use DHCP Snooping, Option 82 and Filtering on Rapier , A T -8800 and A T -8600 Ser ies Switc hes or How T o Use DHCP Snooping, Option 82 and Filtering on x900 Ser ies Switches . These How[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 17 Identifying the user Using DHCP snooping to track clients If yo u r D H C P s e r ve r s u p po r ts i t , yo u c an u s e “option 82” to record mor e information about DHCP clients. This enhances y o ur ability to track users. The switch can pass option 82 information [...]

Pro tecting the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 18 Pr otecting the user This section describes the following methods of pr otecting users fr om other users on the network: z “Using private VLANs” on page 18 . This feature isolates s witch por ts in a VLAN from other switch ports in the same VLAN. z [...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 19 Pro tecting the user Example T o create a private VLAN with por ts 2-6 in it, with an uplink trunk group of por ts 24 and 2 5: create vlan=example vid=2 private add vlan=2 port=24-25 frame=tagged uplink add vlan=2 port=2-6 T o re move ports from the VLAN: # remove port 4: d[...]

Pro tecting the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 20 The following figur e shows a network that can use either local pr oxy ARP or MA C-for ced forwar ding—the examples in both the fo llowing sections r efer to this netw ork. Local pr oxy ARP In a network configuration lik e the pre vious figure, each e[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 21 Pro tecting the user Configuration of edge swi tc hes 1. Create the VLANs, specifying that the y are pr ivate. Mak e a different VLAN for each type of traffic that y o u want to contr ol differentl y . 2. Add the uplink and private por ts to the VLANs as tagged ports. 3. Co[...]

Pro tecting the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 22 Use the following configuration f or edge s witches 2 and 3 (A T -8648 s witches in this example): ena stp=default set stp=default mode=rapid create vlan="voice" vid=101 private add vlan=101 port=49-50 uplink frame=tagged add vlan=101 port=1-4[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 23 Pro tecting the user # Create a classifier to match all traffic in VLANs 101-104 create class=10 ipsa=192.168.0.0/16 ipda=192.168.0.0/16 # Create a classifier to match voice traffic create class=100 ipsa=192.168.1.0/24 ipda=192.168.1.0/24 # Create a classifier to match mana[...]

Pro tecting the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 24 Configuration of edge swi tc hes 1. Create a VLAN f or each type of ser vice (for example , voice, video, and data). With so ftw are vers io ns 2 91 -04 and ea rli er , th e V LAN s mu st b e pr iv ate VLA Ns . W ith so ftw are versions 291-05 and later[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 25 Pro tecting the user z Ho w T o Configure Micr osoft® Windows XP Vir tual Private Network (V PN) c lient inter operability without NA T -T suppor t z Ho w T o Configure Micr osoft® Windows XP Vir tual Private Network (V PN) c lient inter operability with NA T -T suppor t [...]

Pro tecting the user Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 26 T o block the W32.Slammer worm on port 1 , which does not ha ve an SQL client or s er ver attached to it: create classifier=1 udpdport=1434 protocol=ip iport=1 add switch hwfilter classifier=1 action=discard Blocking worms thr ough QoS actions On A T -8[...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 27 Appendix: Configuration scripts for MA C-forced f orwarding example Appendix: Configuration scripts for MA C-for ced forwar ding example In this example (fr om page 23 ), the edge switches can be an y of the following switches: z Rapier 1 6fi and Rapier 24i (but not Rapier [...]

Appendix: Configuration scripts for MA C-forced f orwarding example Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 28 Edge s witch 2 Edge switch 2 is connected to port 50 of edge switch 1 . The configuration is similar to edge swi tc h 1 —differ enc es are in bold : # System configuration set system name="Edge Swit [...]

Create A Secure Netw ork With Allied T elesis Managed La yer 3 Sw itches 29 Appendix: Configuration scripts for MA C-forced f orwarding example Edge s witch 3 Edge switch 3 is connected to port 49 of edge switch 1 . The configuration is similar to edge swi tc h 1 —differ enc es are in bold : # System configuration set system name="Edge Swit [...]

Appendix: Configuration scripts for MA C-forced f orwarding example Creat e A Secure Netw ork With Allied T elesis Managed La yer 3 Switches 30 Access Router set system name="Access Ro uter" # Create a VLAN for access ing the Internet, SIP server and multicast groups create vlan=CoreNetwork vi d=28 # Create the other VLANs create vlan=Voi[...]

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