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DHCP-Relay relay request for tagged and untagged

MarcoScholl

Hi

i have a problem with the dhcp relay. we have a red 50 with an interface thats tagged as 10. on the xg firewall we have a reds1 and reds1.10 interface with a dhcp relay.

when i now request an ip adress i got 2 request on dhcp server. one for reds1 and one for reds1.10. thats not good because the client can get an invalid ipadress.



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  • 0

    Hi Marco,

    reds1 interface (physical interface) receives dhcp request with vlan tagged 10 & then that packet will be submitted to sub interference i.e. reds1.10.

    Regards,

    Vishal Patel

  • 0 in reply to vishaljpatel

    but why i get a dhcp request for reds1 subnet, too?

  • 0 in reply to MarcoScholl

    Hi Marco,

    Suspecting some configuration issue. May I have some setup details & red configuration details?

    There might be a chance wherein red device receiving two different dhcp requests tagged & untagged.

    Regards,

    Vishal Patel

  • 0 in reply to vishaljpatel

    The RED Port 1 is configured as "Hybrid Port" with VLAN(s) "9" and Port 2 is configured as "Untagged Port, drop tagged" with VLAN 10.

    Wenn i start dhcp request on Port 1 (as untagged), i can see the request on resd1 but i didn't get an dhcp answer on Port 1

    reds1, IN: IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from f0:de:f1:cd:18:a3 (oui Unknown), length 300
    reds1, OUT: IP 10.108.254.254.bootps > 10.108.4.245.bootpc: BOOTP/DHCP, Reply, length 300

    When i start dhcp request on Port 2 (as untagged), i can see the request on reds1 and reds1.2.

    On DHCP got requests from both relays

    test-dhcpd01.hostings.i22.de dhcpd: DHCPACK to 10.208.254.100 (f0:de:f1:cd:18:a3) via eth0
    test-dhcpd01.hostings.i22.de dhcpd: DHCPINFORM from 10.208.254.100 via 10.108.254.254

    test-dhcpd01.hostings.i22.de dhcpd: DHCPREQUEST for 10.208.254.100 from f0:de:f1:cd:18:a3 via 10.108.254.254: wrong network.
    test-dhcpd01.hostings.i22.de dhcpd: DHCPNAK on 10.208.254.100 to f0:de:f1:cd:18:a3 via 10.108.254.254

    reds1, IN: IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from f0:de:f1:cd:18:a3 (oui Unknown), length 310
    reds1, OUT: IP 10.108.254.254.bootps > 255.255.255.255.bootpc: BOOTP/DHCP, Reply, length 300 <- subnet of reds1
    reds1, OUT: IP 10.208.254.254.bootps > 10.208.254.100.bootpc: BOOTP/DHCP, Reply, length 300 <- subnet of reds1.2

    My Workaround -> Don't use hybrid port. All data should tagged, than works all fine. but i must configre a dummy ip for untagged reds1 interface