@michaelv Are you using a custom STM32 board?
The issue is not getting reproduced on STM32F4 NUCLEO board. [NUCLEO-F439ZI]
Verified using the current main branch of +TCP. This board uses lan8742a as its PHY.
The debug logs looks like this:
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dns query6: 'google.nl' = 2404:6800:4007:829::2003 rc = 0
Server task now ready.
pxEasyFit: ARP 192.168.0.1 -> 192.168.0.102
ipARP_REQUEST from 192.168.0.1 to 192.168.0.102 end-point 192.168.0.102
/********** UNPLUGGED ETHERNET CABLE **********/
xPhyCheckLinkStatus: PHY LS now 00
prvEthernetUpdateConfig: LS mask 00 Force 0
vIPSetDHCP_RATimerEnableState: Off
prvCloseDHCPSocket[44-46]: closed, user count 0
vIPSetDHCP_RATimerEnableState: Off
prvCloseDHCPSocket[44-46]: closed, user count 0
vIPSetDHCP_RATimerEnableState: Off
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/********** PLUGGED ETHERNET CABLE BACK **********/
Link Status is high
vDHCPProcessEndPoint: enter 0
DHCP-socket[44-46]: DHCP Socket Create
prvCreateDHCPSocket[44-46]: open, user count 1
prvInitialiseDHCP: start after 250 ticks
vDHCP_RATimerReload: 250
vDHCPProcessEndPoint: exit 1
RA: source fe80::7009
vRAProcess: Router Solicitation, attempt 1/3
vRAProcess( 1, 2001:470:ed44::a90f:aeca:eb09:e37f) bRouterReplied=0 bIPAddressInUse=0 state 6 -> 1
RA: Reload 10 seconds
vDHCP_RATimerReload: 10000
IP-address : fe80::7009
End-point : up = yes method static
Prefix : fe80::/10
GW : ::
DNS-0 : ::
DNS-1 : ::
MAC address: 00-11-22-33-44-46
vDHCPProcessEndPoint: enter 1
vDHCPProcess: discover
vDHCPProcessEndPoint: exit 2
vDHCPProcessEndPoint: enter 2
Autonego ready: 00000004: full duplex 100 mbit high status
vDHCPProcess: offer 192.168.0.102 for MAC address 44-46
vDHCPProcess: reply 192.168.0.102
vDHCPProcessEndPoint: exit 3
pxEasyFit: ARP 192.168.0.1 -> 192.168.0.102
ipARP_REQUEST from 192.168.0.1 to 192.168.0.102 end-point 0.0.0.0
vDHCPProcessEndPoint: enter 3
vDHCPProcess: offer 192.168.0.102 for MAC address 44-46
vDHCPProcess: acked 192.168.0.102
IP-address : 192.168.0.102
Default IP : 192.168.2.114
End-point : up = yes method DHCP
Net mask : 255.255.255.0
GW : 192.168.0.1
DNS-0 : 192.168.0.1
DNS-1 : 0.0.0.0
Broadcast : 192.168.0.255
MAC address: 00-11-22-33-44-46