Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Untitled

Assume the following setup:

Subnet: 192.168.1.0 with Mask: 255.255.255.0

Range: 192.168.1.10-192.168.1.50

Domain Name: noname.com

Domain Server: 192.168.1.1

DHCP SETUP

The following instructions are for DHCP. Please see OES documentation for details:

  1. Create a service
  2. Create a DHCP Server object with the following two settings:
    1. ddns-rev-domainname in-addr.arpa
    2. ddns-update-style interim
  3. Create the following two zone objects:
    1. Zone Name: noname.com with DNS Server IP address of 192.168.1.1
    2. Zone Name: 1.168.192.in-addr.arpa with DNS Server IP address of 192.168.1.1
      • NOTE: The zone names created here must match the zones names as they are found under DNS
  4. Create a subnet with the following settings:
    • Subnet IP Address: 192.168.1.0
    • Mask: 255.255.255.0
  5. View/Modify the newly created subnet and add noname.com for DNS Zone for Dynamic Update
  6. Create a Pool with the range specified at the beginning: Start of 192.168.1.10 and end of 192.168.1.50
  7. View/Modify the newly create Pool and change DNS Update to Always Update

DHCP configuration is complete.

DNS SETUP

The following instructions are for DNS. Please see the OES documentation for details:

  1. Create the following two DNS zones:
    1. noname.com
    2. An in-addr.arpa zone similar to this: 1.168.192.in-addr.arpa zone (Type in the address normally in the boxes (192.168.1) leaving the last box blank. The application will complete the process to give you a 1.168.192.in-addr.arpa zone).
  2. On each zone select the Control Lists tab and in the ALLOW UPDATE option. Add an entry of “any” in the filter (default is blank)

DNS Configuration is complete.

Test DDNS:

  1. Start named (rcnovell-named start)
  2. Start dhcp (rcdhcpd start)
  3. Release and renew dhcp leases from the workstation

If the setup is not working, check the following files:

  • /var/log/messages for error messages
  • /var/lib/dhcp/db/dhcpd.leases. Along with the lease information you should see:
    • For a PTR record: set ddns-rev-name=”10.1.168.192.in-addr.arpa”
    • For an A record: set ddns-fwd-name=”workstation.noname.com”

Related:

  • No Related Posts

Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers DHCP Denial of Service Vulnerability

A vulnerability in the DHCP message handler of Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, remote attacker to cause the supervisor to crash, which could result in a denial of service (DoS) condition.

The vulnerability is due to insufficient error handling when DHCP version 4 (DHCPv4) messages are parsed. An attacker could exploit this vulnerability by sending a malicious DHCPv4 message to or through a WAN interface of an affected device. A successful exploit could allow the attacker to cause a reload of the affected device.

Note: On Cisco cBR-8 Converged Broadband Routers, all of the following are considered WAN interfaces:

  • 10 Gbps Ethernet interfaces
  • 100 Gbps Ethernet interfaces
  • Port channel interfaces that include multiple 10 and/or 100 Gbps Ethernet interfaces

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-dhcp-dos-JSCKX43h

This advisory is part of the September 24, 2020, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 25 Cisco Security Advisories that describe 34 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: September 2020 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.

Security Impact Rating: High

CVE: CVE-2020-3509

Related: