DHCP client oddness in FLEX H

PeterUK

DHCP client oddness in FLEX H

USG FLEX 200H V1.31(ABWV.0)ITS-0311-GUI

Also to note DHCP client is slow to re-get a IP on unplug replug Ethernet plug routing rules with ping on the given interfere take time to enable the rules on ping success.

So on FLEX H I have WAN2 on P2 that gets the WAN IP virgin media and VLAN31 External
192.168.31.2/30
192.168.31.1
Which points to my VPN300 that has routes out Ge4 to my FWA510 by EE

At first I was like what on earth is going on! So I Wireshark right up to My virgin media and see this when I trigger a FLEX H to do DHCP (unplug replug)

I know right whats that EE IP doing on my virgin media! With the right DHCP info!

So on VPN300 VLAN31 I did a packet capture so the FLEX P2 WAN2 receives Offer and ACK then for some reason forwards then out VLAN31 to my VPN300 which then sends them out FWA510 by EE (as SNAT source port) to come right back around to my virgin media! This is a bug? in the mean time I have disabled VLAN31 on VPN300 I don't think it can cause a issue but is not right.

Zyxel_Melen

Hi @PeterUK,

So the issue is that when port 2/ge2 unplug & replug to get DHCP, but the H also sends the DHCP packet to VLAN 31/port 4(external interface). Is this summary correct?

Could you also share these packets with me?

PeterUK

Yes correct I send you a new packet capture