I've been trying to resolve this issue for a few months now and finally
have reached the point where I thought reaching out on here might yield
some more useful insights.
I recently added IPv6 configuration to my OpenBSD router and since then
I get an LCP timeout every 2-3 days from which it never recovers.
Looking at the debug output from pppoe it attempts to reconnect but when
sending the PADI to reinitialise the connection there is an ENOBUFS
error. This seems to lock the whole system up, I can't even log in
locally it just hangs after receiving the username and password, and
after a reboot everything reconnects and starts working immediately.
Could the addition of IPv6 and related PF rules have caused it to start
to hit max clusters? I don't see any other related issues in messages
around hitting that limit which I would have expected to see.
Everything was working without any issues until the addition of the IPv6
connection.
I've tried to include as much information here as I have but please let
me know if more would be useful and I'll grab it.
Really I just want to know if bumping kern.maxclusters is the correct
solution here, and if so is there some guide or handy rule of thumb as
to by how much?
# Example /var/log/messages output from a failure:
Jan 13 00:17:03 farpoint /bsd: pppoe0 (8864) state=3, session=0x8c7 output ->
f8:13:08:40:d1:28, len=48
Jan 13 00:17:06 farpoint /bsd: pppoe0 (8864) state=3, session=0x8c7 output ->
f8:13:08:40:d1:28, len=517
Jan 13 00:17:08 farpoint /bsd: pppoe0 (8864) state=3, session=0x8c7 output ->
f8:13:08:40:d1:28, len=48
Jan 13 00:17:13 farpoint /bsd: pppoe0: LCP keepalive timeout
Jan 13 00:17:13 farpoint /bsd: pppoe0: lcp close(opened)
Jan 13 00:17:13 farpoint /bsd: pppoe0: lcp opened->closing
Jan 13 00:17:13 farpoint /bsd: pppoe0: phase terminate
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipcp down(opened)
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipcp opened->starting
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipcp close(starting)
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipcp starting->initial
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipv6cp down(opened)
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipv6cp opened->starting
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipv6cp close(starting)
Jan 13 00:17:13 farpoint /bsd: pppoe0: ipv6cp starting->initial
Jan 13 00:17:13 farpoint /bsd: pppoe0: lcp closing->stopped
Jan 13 00:17:13 farpoint /bsd: pppoe0: timeout
Jan 13 00:17:13 farpoint /bsd: pppoe0: disconnecting
Jan 13 00:17:13 farpoint /bsd: pppoe0: lcp down(stopped)
Jan 13 00:17:13 farpoint /bsd: pppoe0: lcp stopped->starting
Jan 13 00:17:13 farpoint /bsd: pppoe0: phase establish
Jan 13 00:17:13 farpoint /bsd: pppoe0: failed to send PADI, error=55
Jan 13 00:17:13 farpoint /bsd: pppoe0: Down event (carrier loss), taking
interface down.<7>pppoe0: lcp close(starting)
Jan 13 00:17:13 farpoint /bsd: pppoe0: lcp starting->initial
Jan 13 00:17:13 farpoint /bsd: pppoe0: phase dead
Jan 13 00:17:18 farpoint /bsd: pppoe0: timeout
Jan 13 00:17:18 farpoint /bsd: pppoe0: failed to transmit PADI, error=55
Jan 13 00:17:33 farpoint /bsd: pppoe0: timeout
# repeat the last two messages until a reboot
# /etc/hostname.pppoe0
mtu 1500
inet 0.0.0.0 255.255.255.255 NONE \
pppoedev igc0 \
authproto chap \
authname username \
authkey password \
up
dest 0.0.0.1
inet6 eui64
inet6 alias 2001:8b0:1111:1111:0:ffff:5a9b:4f7d/128
!/sbin/route add default -ifp \$if 0.0.0.1
!/sbin/route add -inet6 default -ifp \$if fe80::%\$if
# /etc/hostname.igc0
mtu 1508
up
# pfctl -s rules
match all scrub (no-df random-id reassemble tcp)
match out on egress inet from ! (egress:network) to any nat-to (egress:0)
round-robin
match out on egress inet6 from fd02:65c8:c718:cafe::/64 to any nat-to (egress)
round-robin
match in on lan inet6 from any to 64:ff9b::5a9b:4f7d rdr-to ::1
block drop in quick from urpf-failed to any
block drop all
pass out quick all flags S/SA
pass in inet proto icmp all
pass in inet6 proto ipv6-icmp all
pass in inet6 proto udp from fe80::/10 port = 547 to fe80::/10 port = 546 no
state
pass in proto tcp from any to (egress) port = 80 flags S/SA
pass in proto tcp from any to (egress) port = 443 flags S/SA
pass in proto tcp from any to (egress) port = 25 flags S/SA
pass in proto udp from any to (egress) port = 51820
pass in on lan all flags S/SA
pass in on lan inet6 from any to 64:ff9b::/96 flags S/SA af-to inet from
(egress:0) round-robin
# sysctl kern.maxclusters
kern.maxclusters=262144
# netstat -m
3388 mbufs in use:
3242 mbufs allocated to data
88 mbufs allocated to packet headers
58 mbufs allocated to socket names and addresses
2471/2552 mbuf 2048 byte clusters in use (current/peak)
349/510 mbuf 2112 byte clusters in use (current/peak)
0/40 mbuf 4096 byte clusters in use (current/peak)
0/40 mbuf 8192 byte clusters in use (current/peak)
0/14 mbuf 9216 byte clusters in use (current/peak)
0/40 mbuf 12288 byte clusters in use (current/peak)
0/8 mbuf 16384 byte clusters in use (current/peak)
0/32 mbuf 65536 byte clusters in use (current/peak)
10364/10364/524288 Kbytes allocated to network (current/peak/max)
0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines
0 defrag mbuf allocation
1921444 prepend mbuf allocation
0 pullup mbuf allocation
0 pullup memory copy
0 pulldown mbuf allocation
0 pulldown memory copy
# dmesg
OpenBSD 7.8 (GENERIC.MP) #1: Sat Nov 29 11:02:59 MST 2025
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
real mem = 51243216896 (48869MB)
avail mem = 49662828544 (47362MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 3.6 @ 0x73bbd000 (137 entries)
bios0: vendor iKOOLCORE version "v1.1" date 12/17/2024
bios0: iKOOLCORE R2Max
efi0 at bios0: UEFI 2.8
efi0: American Megatrends rev 0x5001b
acpi0 at bios0: ACPI 6.5
acpi0: sleep states S0 S3 S4 S5
acpi0: tables DSDT FACP FIDT SSDT SSDT SSDT SSDT SSDT HPET APIC MCFG SSDT UEFI
SDEV NHLT LPIT SSDT SSDT DBGP DBG2 SSDT DMAR FPDT SSDT SSDT SSDT SSDT PHAT TPM2
WSMT
acpi0: wakeup devices PEGP(S4) PEGP(S4) PEGP(S4) SIO1(S3) RP09(S4) PXSX(S4)
RP10(S4) PXSX(S4) RP11(S4) PXSX(S4) RP12(S4) PXSX(S4) RP13(S4) PXSX(S4)
RP14(S4) PXSX(S4) [...]
acpitimer0 at acpi0: 3579545 Hz, 24 bits
acpihpet0 at acpi0: 19200000 Hz
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Core(TM) i3-N305, 1977.40 MHz, 06-be-00, patch 0000001d
cpu0: cpuid 1
edx=bfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
ecx=77fafbbf<SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND>
cpu0: cpuid 6 eax=578ff7<SENSOR,ARAT,PTS> ecx=9<EFFFREQ>
cpu0: cpuid 7.0
ebx=239ca7eb<FSGSBASE,TSC_ADJUST,BMI1,AVX2,SMEP,BMI2,ERMS,INVPCID,RDSEED,ADX,SMAP,CLFLUSHOPT,CLWB,PT,SHA>
ecx=98c007ac<UMIP,PKU,WAITPKG,PKS>
edx=fc184410<MD_CLEAR,IBT,IBRS,IBPB,STIBP,L1DF,SSBD>
cpu0: cpuid a vers=5, gp=6, gpwidth=48, ff=3, ffwidth=48
cpu0: cpuid d.1 eax=f<XSAVEOPT,XSAVEC,XGETBV1,XSAVES>
cpu0: cpuid 80000001 edx=2c100800<NXE,PAGE1GB,RDTSCP,LONG>
ecx=121<LAHF,ABM,3DNOWP>
cpu0: cpuid 80000007 edx=100<ITSC>
cpu0: msr
10a=15c0fd6b<IBRS_ALL,SKIP_L1DFL,MDS_NO,IF_PSCHANGE,TAA_NO,MISC_PKG_CT,ENERGY_FILT,DOITM,SBDR_SSDP_N,FBSDP_NO,PSDP_NO,OVERCLOCK,PBRSB_NO,GDS_NO,RFDS_CLEAR>
cpu0: 32KB 64b/line 8-way D-cache, 64KB 64b/line 8-way I-cache, 2MB 64b/line
16-way L2 cache, 6MB 64b/line 12-way L3 cache
cpu0: smt 0, core 0, package 0
mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges
cpu0: apic clock running at 38MHz
cpu0: mwait min=64, max=64, C-substates=0.2.0.2.0.1.0.1, IBE
cpu1 at mainbus0: apid 2 (application processor)
cpu1: Intel(R) Core(TM) i3-N305, 1698.51 MHz, 06-be-00, patch 0000001d
cpu1: smt 0, core 1, package 0
cpu2 at mainbus0: apid 4 (application processor)
cpu2: Intel(R) Core(TM) i3-N305, 1696.09 MHz, 06-be-00, patch 0000001d
cpu2: smt 0, core 2, package 0
cpu3 at mainbus0: apid 6 (application processor)
cpu3: Intel(R) Core(TM) i3-N305, 1696.09 MHz, 06-be-00, patch 0000001d
cpu3: smt 0, core 3, package 0
cpu4 at mainbus0: apid 8 (application processor)
cpu4: Intel(R) Core(TM) i3-N305, 1696.11 MHz, 06-be-00, patch 0000001d
cpu4: smt 0, core 4, package 0
cpu5 at mainbus0: apid 10 (application processor)
cpu5: Intel(R) Core(TM) i3-N305, 1696.09 MHz, 06-be-00, patch 0000001d
cpu5: smt 0, core 5, package 0
cpu6 at mainbus0: apid 12 (application processor)
cpu6: Intel(R) Core(TM) i3-N305, 1696.09 MHz, 06-be-00, patch 0000001d
cpu6: smt 0, core 6, package 0
cpu7 at mainbus0: apid 14 (application processor)
cpu7: Intel(R) Core(TM) i3-N305, 1696.09 MHz, 06-be-00, patch 0000001d
cpu7: smt 0, core 7, package 0
ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 120 pins
acpimcfg0 at acpi0
acpimcfg0: addr 0xc0000000, bus 0-255
acpiprt0 at acpi0: bus 0 (PC00)
acpiprt1 at acpi0: bus 7 (RP09)
acpiprt2 at acpi0: bus -1 (RP10)
acpiprt3 at acpi0: bus 8 (RP11)
acpiprt4 at acpi0: bus -1 (RP12)
acpiprt5 at acpi0: bus -1 (RP13)
acpiprt6 at acpi0: bus -1 (RP14)
acpiprt7 at acpi0: bus -1 (RP15)
acpiprt8 at acpi0: bus -1 (RP16)
acpiprt9 at acpi0: bus -1 (RP01)
acpiprt10 at acpi0: bus -1 (RP02)
acpiprt11 at acpi0: bus 1 (RP03)
acpiprt12 at acpi0: bus 2 (RP04)
acpiprt13 at acpi0: bus -1 (RP05)
acpiprt14 at acpi0: bus -1 (RP06)
acpiprt15 at acpi0: bus 3 (RP07)
acpiprt16 at acpi0: bus -1 (RP08)
acpiprt17 at acpi0: bus -1 (RP17)
acpiprt18 at acpi0: bus -1 (RP18)
acpiprt19 at acpi0: bus -1 (RP19)
acpiprt20 at acpi0: bus -1 (RP20)
acpiprt21 at acpi0: bus -1 (RP21)
acpiprt22 at acpi0: bus -1 (RP22)
acpiprt23 at acpi0: bus -1 (RP23)
acpiprt24 at acpi0: bus -1 (RP24)
acpiec0 at acpi0: not present
acpipci0 at acpi0 PC00: 0x00000010 0x00000011 0x00000000
com0 at acpi0 UAR1 addr 0x3f8/0x8 irq 4: ns16550a, 16 byte fifo
"ACPI000E" at acpi0 not configured
acpibtn0 at acpi0: SLPB
acpicpu0 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu1 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu2 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu3 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu4 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu5 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu6 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
acpicpu7 at acpi0: C3(200@1048 mwait.1@0x60), C2(350@127 mwait.1@0x21),
C1(1000@1 mwait.1), PSS
"PNP0C14" at acpi0 not configured
"PNP0C14" at acpi0 not configured
intelpmc0 at acpi0: PEPD
state 0: 0x7f:1:2:0x00:0x0000000000000060
counter: 0x7f:64:0:0x00:0x0000000000000632
frequency: 0
state 1: 0x7f:1:2:0x00:0x0000000000000060
counter: 0x00:32:0:0x03:0x00000000fe00193c
frequency: 8197
acpibtn1 at acpi0: PWRB
tpm0 at acpi0 TPM_ 2.0 (CRB) addr 0xfed40000/0x5000, device 0x00000000 rev 0x0
"PNP0C0B" at acpi0 not configured
"PNP0C0B" at acpi0 not configured
"PNP0C0B" at acpi0 not configured
"PNP0C0B" at acpi0 not configured
"PNP0C0B" at acpi0 not configured
acpipwrres0 at acpi0: WRST
acpipwrres1 at acpi0: TBT0, resource for TDM0, TRP0, TRP1
acpipwrres2 at acpi0: TBT1, resource for TDM1, TRP2, TRP3
acpipwrres3 at acpi0: FN00, resource for FAN0
acpipwrres4 at acpi0: FN01, resource for FAN1
acpipwrres5 at acpi0: FN02, resource for FAN2
acpipwrres6 at acpi0: FN03, resource for FAN3
acpipwrres7 at acpi0: FN04, resource for FAN4
acpitz0 at acpi0
acpitz0: critical temperature is 110 degC
acpipwrres8 at acpi0: PIN_
acpivideo0 at acpi0: GFX0
acpivout0 at acpivideo0: DD1F
acpivout1 at acpivideo0: DD2F
cpu0: using VERW MDS workaround
cpu0: Enhanced SpeedStep 1977 MHz: speeds: 1801, 1800, 1700, 1600, 1500, 1400,
1300, 1200, 1100, 1000, 900, 800 MHz
pci0 at mainbus0 bus 0
0:31:5: mem address conflict 0xfe010000/0x1000
pchb0 at pci0 dev 0 function 0 "Intel ADL-N Host" rev 0x00
inteldrm0 at pci0 dev 2 function 0 "Intel Graphics" rev 0x00
drm0 at inteldrm0
inteldrm0: msi, ALDERLAKE_P, gen 12
xhci0 at pci0 dev 13 function 0 "Intel ADL-N xHCI" rev 0x00: msi, xHCI 1.20
usb0 at xhci0: USB revision 3.0
uhub0 at usb0 configuration 1 interface 0 "Intel xHCI root hub" rev 3.00/1.00
addr 1
xhci1 at pci0 dev 20 function 0 "Intel ADL-N xHCI" rev 0x00: msi, xHCI 1.20
usb1 at xhci1: USB revision 3.0
uhub1 at usb1 configuration 1 interface 0 "Intel xHCI root hub" rev 3.00/1.00
addr 1
"Intel ADL-N SRAM" rev 0x00 at pci0 dev 20 function 2 not configured
"Intel ADL-N HECI" rev 0x00 at pci0 dev 22 function 0 not configured
ppb0 at pci0 dev 28 function 0 "Intel ADL-N PCIE" rev 0x00: msi
pci1 at ppb0 bus 1
igc0 at pci1 dev 0 function 0 "Intel I226-V" rev 0x04, msix, 4 queues, address
00:e2:59:01:7e:33
ppb1 at pci0 dev 28 function 3 "Intel ADL-N PCIE" rev 0x00: msi
pci2 at ppb1 bus 2
igc1 at pci2 dev 0 function 0 "Intel I226-V" rev 0x04, msix, 4 queues, address
00:e2:59:01:7e:34
ppb2 at pci0 dev 28 function 6 "Intel ADL-N PCIE" rev 0x00: msi
pci3 at ppb2 bus 3
ppb3 at pci3 dev 0 function 0 "ASMedia ASM1182e" rev 0x00
pci4 at ppb3 bus 4
ppb4 at pci4 dev 3 function 0 "ASMedia ASM1182e" rev 0x00: msi
pci5 at ppb4 bus 5
nvme0 at pci5 dev 0 function 0 "SanDisk WD Black" rev 0x00: msix, NVMe 1.3
nvme0: WD Red SN700 1000GB, firmware 111150WD, serial 24340A800193
scsibus1 at nvme0: 2 targets, initiator 0
sd0 at scsibus1 targ 1 lun 0: <NVMe, WD Red SN700 100, 1111>
sd0: 953869MB, 512 bytes/sector, 1953525168 sectors
ppb5 at pci4 dev 7 function 0 "ASMedia ASM1182e" rev 0x00: msi
pci6 at ppb5 bus 6
nvme1 at pci6 dev 0 function 0 "SanDisk WD Black" rev 0x00: msix, NVMe 1.3
nvme1: WD Red SN700 1000GB, firmware 111150WD, serial 24340A800050
scsibus2 at nvme1: 2 targets, initiator 0
sd1 at scsibus2 targ 1 lun 0: <NVMe, WD Red SN700 100, 1111>
sd1: 953869MB, 512 bytes/sector, 1953525168 sectors
ppb6 at pci0 dev 29 function 0 "Intel ADL-N PCIE" rev 0x00: msi
pci7 at ppb6 bus 7
aq0 at pci7 dev 0 function 0 "Aquantia AQC113C" rev 0x03: msix, 8 queues,
Atlantic2 B0, F/W version 1.3.21, address 00:e2:59:01:7e:35
ppb7 at pci0 dev 29 function 2 "Intel ADL-N PCIE" rev 0x00: msi
pci8 at ppb7 bus 8
aq1 at pci8 dev 0 function 0 "Aquantia AQC113C" rev 0x03: msix, 8 queues,
Atlantic2 B0, F/W version 1.3.21, address 00:e2:59:01:7e:36
pcib0 at pci0 dev 31 function 0 "Intel ADL-N eSPI" rev 0x00
azalia0 at pci0 dev 31 function 3 "Intel ADL-N HD Audio" rev 0x00: msi
azalia0: no HD-Audio codecs
ichiic0 at pci0 dev 31 function 4 "Intel ADL-N SMBus" rev 0x00: apic 2 int 16
iic0 at ichiic0
iic0: addr 0x48 15=04 19=04 1b=05 20=01 22=03 26=03 28=03 2a=02 2b=02 2d=02
2e=04 2f=02 34=06 3b=02 3c=02 3d=04 words 00=0000 01=0000 02=0000 03=0000
04=0000 05=0000 06=0000 07=0000
"eeprom" at iic0 addr 0x50 not configured
"Intel ADL-N SPI" rev 0x00 at pci0 dev 31 function 5 not configured
isa0 at pcib0
isadma0 at isa0
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
vmm0 at mainbus0: VMX/EPT
efifb at mainbus0 not configured
umass0 at uhub1 port 6 configuration 1 interface 0 "USB Storage USB Storage"
rev 2.00/14.04 addr 2
umass0: using SCSI over Bulk-Only
scsibus3 at umass0: 2 targets, initiator 0
sd2 at scsibus3 targ 1 lun 0: <Generic, STORAGE DEVICE, 1404> removable
sd2: 30560MB, 512 bytes/sector, 62586880 sectors
vscsi0 at root
scsibus4 at vscsi0: 256 targets
softraid0 at root
scsibus5 at softraid0: 256 targets
softraid0: sd3 was not shutdown properly
sd3 at scsibus5 targ 1 lun 0: <OPENBSD, SR RAID 1C, 006>
sd3: 953609MB, 512 bytes/sector, 1952992063 sectors
root on sd3a (c8993d4300918841.a) swap on sd3b dump on sd3b
WARNING: / was not properly unmounted
inteldrm0: 1024x768, 32bpp
wsdisplay0 at inteldrm0 mux 1
wsdisplay0: screen 0-5 added (std, vt100 emulation)
