<div dir="ltr"><div>Next I tried listening on the veth that LXC creates when the container is started. Once it was up, I logged into the LXC container nsa2 and ran the command "dhclient" at the command line of the container. Now I see some traffic on ports 67 and 68 as follows but still not understanding what is happening here.<br></div><div><br></div><div>vethLVRkjQ: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500<br> inet6 fe80::fcb2:39ff:fe74:cb61 prefixlen 64 scopeid 0x20<link><br> ether fe:b2:39:74:cb:61 txqueuelen 1000 (Ethernet)<br> RX packets 7 bytes 586 (586.0 B)<br> RX errors 0 dropped 0 overruns 0 frame 0<br> TX packets 14 bytes 1224 (1.1 KiB)<br> TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0<br><br>[ubuntu@f33sv1 ~]$ sudo tcpdump -i vethLVRkjQ -vvv -s 1500 '((port 67 or port 68))'<br>dropped privs to tcpdump<br>tcpdump: listening on vethLVRkjQ, link-type EN10MB (Ethernet), capture size 1500 bytes<br>08:57:05.392702 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)<br> 0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:16:3e:13:70:7c (oui Unknown), length 300, xid 0xb7304d0f, Flags [none] (0x0000)<br> Client-Ethernet-Address 00:16:3e:13:70:7c (oui Unknown)<br> Vendor-rfc1048 Extensions<br> Magic Cookie 0x63825363<br> DHCP-Message Option 53, length 1: Discover<br> Hostname Option 12, length 4: "nsa2"<br> Parameter-Request Option 55, length 13: <br> Subnet-Mask, BR, Time-Zone, Default-Gateway<br> Domain-Name, Domain-Name-Server, Option 119, Hostname<br> Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route<br> NTP<br> END Option 255, length 0<br> PAD Option 0, length 0, occurs 35<br>08:57:08.398285 IP (tos 0xc0, ttl 64, id 7927, offset 0, flags [none], proto UDP (17), length 328)<br> f33sv1.bootps > 10.0.3.166.bootpc: [bad udp cksum 0x1bec -> 0x19ab!] BOOTP/DHCP, Reply, length 300, xid 0xb7304d0f, Flags [none] (0x0000)<br> Your-IP 10.0.3.166<br> Server-IP f33sv1<br> Client-Ethernet-Address 00:16:3e:13:70:7c (oui Unknown)<br> Vendor-rfc1048 Extensions<br> Magic Cookie 0x63825363<br> DHCP-Message Option 53, length 1: Offer<br> Server-ID Option 54, length 4: f33sv1<br> Lease-Time Option 51, length 4: 3600<br> RN Option 58, length 4: 1800<br> RB Option 59, length 4: 3150<br> Subnet-Mask Option 1, length 4: 255.255.255.0<br> BR Option 28, length 4: 10.0.3.255<br> Default-Gateway Option 3, length 4: f33sv1<br> Domain-Name-Server Option 6, length 4: f33sv1<br> Domain-Name Option 15, length 3: "lxc"<br> END Option 255, length 0<br> PAD Option 0, length 0, occurs 3<br>08:57:08.398693 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)<br> 0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:16:3e:13:70:7c (oui Unknown), length 300, xid 0xb7304d0f, Flags [none] (0x0000)<br> Client-Ethernet-Address 00:16:3e:13:70:7c (oui Unknown)<br> Vendor-rfc1048 Extensions<br> Magic Cookie 0x63825363<br> DHCP-Message Option 53, length 1: Request<br> Server-ID Option 54, length 4: f33sv1<br> Requested-IP Option 50, length 4: 10.0.3.166<br> Hostname Option 12, length 4: "nsa2"<br> Parameter-Request Option 55, length 13: <br> Subnet-Mask, BR, Time-Zone, Default-Gateway<br> Domain-Name, Domain-Name-Server, Option 119, Hostname<br> Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route<br> NTP<br> END Option 255, length 0<br> PAD Option 0, length 0, occurs 23<br>08:57:08.413078 IP (tos 0xc0, ttl 64, id 7931, offset 0, flags [none], proto UDP (17), length 331)<br> f33sv1.bootps > 10.0.3.166.bootpc: [bad udp cksum 0x1bef -> 0x3afb!] BOOTP/DHCP, Reply, length 303, xid 0xb7304d0f, Flags [none] (0x0000)<br> Your-IP 10.0.3.166<br> Server-IP f33sv1<br> Client-Ethernet-Address 00:16:3e:13:70:7c (oui Unknown)<br> Vendor-rfc1048 Extensions<br> Magic Cookie 0x63825363<br> DHCP-Message Option 53, length 1: ACK<br> Server-ID Option 54, length 4: f33sv1<br> Lease-Time Option 51, length 4: 3600<br> RN Option 58, length 4: 1800<br> RB Option 59, length 4: 3150<br> Subnet-Mask Option 1, length 4: 255.255.255.0<br> BR Option 28, length 4: 10.0.3.255<br> Default-Gateway Option 3, length 4: f33sv1<br> Domain-Name-Server Option 6, length 4: f33sv1<br> Domain-Name Option 15, length 3: "lxc"<br> Hostname Option 12, length 4: "nsa2"<br> END Option 255, length 0<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Dec 23, 2020 at 8:40 AM Orabuntu-LXC <<a href="mailto:gilbert@orabuntu-lxc.com">gilbert@orabuntu-lxc.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>I ran tcpdump this morning wide open (when I ran it for port 67 and port 68 there was zero traffic detected when starting the lxc container nsa2). When I ran tcpdump wide open I got the following traffic detected when the lxc container starts. I again tried turning off firewalld completely and this is still what I get as shown below. Wondering what is going on here?<br></div><div><br></div><div>[ubuntu@f33sv1 ~]$ sudo tcpdump -i lxcbr0 -vvv <br>dropped privs to tcpdump<br>tcpdump: listening on lxcbr0, link-type EN10MB (Ethernet), capture size 262144 bytes<br>08:34:39.305449 IP (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 40, options (RA))<br> f33sv1 > <a href="http://igmp.mcast.net" target="_blank">igmp.mcast.net</a>: igmp v3 report, 1 group record(s) [gaddr 224.0.0.252 to_ex { }]<br>08:34:39.305469 IP6 (hlim 1, next-header Options (0) payload length: 76) f33sv1 > ff02::16: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener report v2, 3 group record(s) [gaddr ff02::1:3 to_ex { }] [gaddr ff02::1:ff00:0 to_ex { }] [gaddr ff02::6a to_ex { }]<br>08:34:39.305542 IP6 (hlim 1, next-header Options (0) payload length: 36) :: > ff02::16: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener report v2, 1 group record(s) [gaddr ff02::1:ff13:707c to_ex { }]<br>08:34:39.397672 IP6 (hlim 1, next-header Options (0) payload length: 76) f33sv1 > ff02::16: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener report v2, 3 group record(s) [gaddr ff02::1:3 to_ex { }] [gaddr ff02::1:ff00:0 to_ex { }] [gaddr ff02::6a to_ex { }]<br>08:34:39.445676 IP6 (hlim 1, next-header Options (0) payload length: 36) :: > ff02::16: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener report v2, 1 group record(s) [gaddr ff02::1:ff13:707c to_ex { }]<br>08:34:39.765786 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) :: > ff02::1:ff13:707c: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has fe80::216:3eff:fe13:707c<br> unknown option (14), length 8 (1): <br> 0x0000: f203 5136 6f9a<br>08:34:39.891089 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) f33sv1 > ff02::1:ff13:707c: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has fe80::216:3eff:fe13:707c<br> source link-address option (1), length 8 (1): 00:16:3e:00:00:00<br> 0x0000: 0016 3e00 0000<br>08:34:40.029649 IP (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 40, options (RA))<br> f33sv1 > <a href="http://igmp.mcast.net" target="_blank">igmp.mcast.net</a>: igmp v3 report, 1 group record(s) [gaddr 224.0.0.252 to_ex { }]<br>08:34:40.797778 IP6 (hlim 1, next-header Options (0) payload length: 36) fe80::216:3eff:fe13:707c > ff02::16: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener report v2, 1 group record(s) [gaddr ff02::1:ff13:707c to_ex { }]<br>08:34:40.797796 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::216:3eff:fe13:707c > ff02::2: [icmp6 sum ok] ICMP6, router solicitation, length 16<br> source link-address option (1), length 8 (1): 00:16:3e:13:70:7c<br> 0x0000: 0016 3e13 707c<br>08:34:40.925732 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) f33sv1 > ff02::1:ff13:707c: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has fe80::216:3eff:fe13:707c<br> source link-address option (1), length 8 (1): 00:16:3e:00:00:00<br> 0x0000: 0016 3e00 0000<br>08:34:40.925787 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::216:3eff:fe13:707c > f33sv1: [icmp6 sum ok] ICMP6, neighbor advertisement, length 32, tgt is fe80::216:3eff:fe13:707c, Flags [solicited, override]<br> destination link-address option (2), length 8 (1): 00:16:3e:13:70:7c<br> 0x0000: 0016 3e13 707c<br>08:34:40.925797 IP6 (flowlabel 0xb6a64, hlim 1, next-header TCP (6) payload length: 44) f33sv1.60688 > fe80::216:3eff:fe13:707c.hostmon: Flags [S], cksum 0xebef (incorrect -> 0xb854), seq 2709608773, win 64800, options [mss 1440,sackOK,TS val 789202957 ecr 0,nop,wscale 7,tfo cookiereq,nop,nop], length 0<br>08:34:40.925818 IP6 (flowlabel 0xed86d, hlim 64, next-header TCP (6) payload length: 20) fe80::216:3eff:fe13:707c.hostmon > f33sv1.60688: Flags [R.], cksum 0xebd7 (incorrect -> 0xc74f), seq 0, ack 2709608774, win 0, length 0<br>08:34:41.693783 IP6 (hlim 1, next-header Options (0) payload length: 36) fe80::216:3eff:fe13:707c > ff02::16: HBH (rtalert: 0x0000) (padn) [icmp6 sum ok] ICMP6, multicast listener report v2, 1 group record(s) [gaddr ff02::1:ff13:707c to_ex { }]<br>08:34:44.509930 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 16) fe80::216:3eff:fe13:707c > ff02::2: [icmp6 sum ok] ICMP6, router solicitation, length 16<br> source link-address option (1), length 8 (1): 00:16:3e:13:70:7c<br> 0x0000: 0016 3e13 707c<br>08:34:46.045831 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::216:3eff:fe13:707c > f33sv1: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has f33sv1<br> source link-address option (1), length 8 (1): 00:16:3e:13:70:7c<br> 0x0000: 0016 3e13 707c<br>08:34:46.045891 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 24) f33sv1 > fe80::216:3eff:fe13:707c: [icmp6 sum ok] ICMP6, neighbor advertisement, length 24, tgt is f33sv1, Flags [solicited]</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Dec 23, 2020 at 12:14 AM Orabuntu-LXC <<a href="mailto:gilbert@orabuntu-lxc.com" target="_blank">gilbert@orabuntu-lxc.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Hi, I cannot get dnsmasq to issue a dhcp address via lxc-net on fedora 33. I have compared it to a working system on Ubuntu 20.04 and what I find is that when an lxc container starts, there is DHCPOFFER normal activity in lxc-net status on Ubuntu 20.04, but not on Fedora 33 where the configuration is afaik exactly the same.</div><div><br></div><div>I have tried various firewalld settings in case firewalld was blocking somehow, but nothing has worked including disabling firewalld entirely as well as disabling selinux entirely. Tomorrow I will try tcpdump and see if there are clues there. Thanks!<br></div><div><br>-- <br><div dir="ltr"><div dir="ltr">Gilbert Standen<div>Creator Orabuntu-LXC</div><div>914-261-4594</div><div><a href="mailto:gilbert@orabuntu-lxc.com" target="_blank">gilbert@orabuntu-lxc.com</a></div><div><br></div></div></div></div></div>
</blockquote></div><br clear="all"><br>-- <br><div dir="ltr"><div dir="ltr">Gilbert Standen<div>Creator Orabuntu-LXC</div><div>914-261-4594</div><div><a href="mailto:gilbert@orabuntu-lxc.com" target="_blank">gilbert@orabuntu-lxc.com</a></div><div><br></div></div></div>
</blockquote></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr">Gilbert Standen<div>Creator Orabuntu-LXC</div><div>914-261-4594</div><div><a href="mailto:gilbert@orabuntu-lxc.com" target="_blank">gilbert@orabuntu-lxc.com</a></div><div><br></div></div></div>