Re: em0: No buffer space available for IPv6 traffic but IPv4 is OK
Date: Fri, 18 Aug 2023 21:54:01 UTC
On Fri, Aug 18, 2023 at 1:02 AM José Pérez <fbl@aoek.com> wrote: > Hi, > on this intel em0 > # dmesg |fgrep em0 > em0: <Intel(R) Gigabit CT 82574L> port 0xd800-0xd81f mem > 0xfe9e0000-0xfe9fffff,0xfe9dc000-0xfe9dffff irq 48 at device 0.0 on pci1 > em0: Using 1024 TX descriptors and 1024 RX descriptors > em0: Using 2 RX queues 2 TX queues > em0: Using MSI-X interrupts with 3 vectors > em0: Ethernet address: xx:xx:xx:xx:xx:xx > em0: netmap queues/slots: TX 2/1024, RX 2/1024 > > IPv4 and IPv6 used to work seamlessly for the past 6+ years. > > # ifconfig em0 > em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu > 1500 > > > options=81249b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,LRO,WOL_MAGIC,VLAN_HWFILTER> > ether xx:xx:xx:xx:xx:xx > inet xxx.xxx.xxx.xxx netmask 0xffffff00 broadcast > xxx.xxx.xxx.255 > inet6 fe80::xxxx:xxxx:xxxx:xxxx%em0 prefixlen 64 scopeid 0x1 > inet6 2xxx:xxxx:xxxx:xxxx::1 prefixlen 64 > media: Ethernet autoselect (100baseTX <full-duplex>) > status: active > nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL> > > Nevertheless, now IPv6 traffic does not work anymore: > # ping6 www.google.com > PING6(56=40+8+8 bytes) 2xxx:xxxx:xxxx:xxxx::1 --> 2yyy:yyyy:yyyy:yyyy::1 > ping6: sendmsg: No buffer space available > ping6: wrote www.google.com 16 chars, ret=-1 > > From send(2): > [...] > [ENOBUFS] The system was unable to allocate an internal > buffer. > The operation may succeed when buffers become > available. > > [ENOBUFS] The output queue for a network interface was > full. > This generally indicates that the interface has > stopped sending, but may be caused by transient > congestion. > [...] > > There is little traffic on the interface and it seems that buffers are > available: > # netstat -m > 2108/3472/5580 mbufs in use (current/cache/total) > 2062/1336/3398/1018874 mbuf clusters in use (current/cache/total/max) > 15/1250 mbuf+clusters out of packet secondary zone in use > (current/cache) > [...] > > Interestingly, there is incoming IPv6 local broadcast traffic as sniffed > by > # tcpdump -n -i em0 ip6 > (ICMP6, neighbor solicitation, UDP from LAN link local addresses). > > Has anyone seen this before and can suggest a fix? > > Reboot did not solve, no software updates made, no config changes, just > stop working from one day to the next. > > Thank you. > > -- > José Pérez > Oddly, ENOBUFS is the error I get when my firewall is blocking transmit traffic. There may well be other causes. -- Kevin Oberman, Part time kid herder and retired Network Engineer E-mail: rkoberman@gmail.com PGP Fingerprint: D03FB98AFA78E3B78C1694B318AB39EF1B055683