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DOCSIS2.0 eMTA Discover-offer loop

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Anonymous (not verified)
DOCSIS2.0 eMTA Discover-offer loop

Hello, here is the situation:

1) the CM has no problems, it is registered.
2) the MTA is trying to get the DHCP info and the dhcp is making the offer, but the MTA seems to ignore it for some reason, I suppose the offer package is incomplet and/or wrong, so the MTA falls in a discover-offer loop.

What am I using?
dhcpd on debian
ubr7246 vxr
CM SA with eMTA
ethereal running on the DHCP server interface

I really appreciate any help with this issue.
RGDS,

G

The dhcpd.conf is next:

**************************************************

ddns-update-style none;
default-lease-time 600;
max-lease-time 7200;
log-facility local7;

#DHCP Server Interface declaration
subnet 172.16.6.128 netmask 255.255.255.128 {
}

# Cable modem's subnet declaration
subnet 10.10.10.0 netmask 255.255.255.0 {
option routers 10.10.10.1;
}

# Cable modem's CPE subnet declaration
subnet 10.20.20.0 netmask 255.255.255.0 {
option routers 10.20.20.1;
}

# 2
option time-offset 10800;
# 6
option domain-name-servers 172.16.6.129;
# 7
option log-servers 172.16.6.129;
# 15
option domain-name "net-uno.net";

## TFTP Server configuration
option tftpserver code 66 = string;
option tftpserver "172.16.6.129";
option fn code 67 = string;
option fn "1-1-1-1-1.bin";

## 122 for Cablelabs Client Configuration (RFC 3495)
option space PC-MTA;
option PC-MTA.DHCP-server-1 code 1 = ip-address;
#option PC-MTA.DHCP-server-2 code 2 = ip-address;
#option PC-MTA.Provision-server code 3 = { integer 8, string };
option PC-MTA.Provision-server code 3 = { integer 8, ip-address };
#option PC-MTA.Provision-server code 3 = string;
option PC-MTA.AS-REQ_AS-REP code 4 = { integer 32, integer 32, integer 32 };
option PC-MTA.AP-REQ_AP-REP code 5 = { integer 32, integer 32, integer 32 };
option PC-MTA.Kerberos-realm code 6 = string;
option PC-MTA.TGS-util code 7 = integer 8;
option PC-MTA.Provision-timer code 8 = integer 8;
option PC-MTA.Ticket-ctrl-mask code 9 = integer 16;
option PC-MTA-122 code 122 = encapsulate PC-MTA;

host CM-SA {
hardware ethernet 00:0f:21:79:d7:74;
option host-name "C01";
fixed-address 10.10.10.4;
option PC-MTA.DHCP-server-1 172.16.6.129;
}

host MTA-SA {
hardware ethernet 00:0f:21:79:d7:76;
option host-name "emta1";
filename "mta.bin";
fixed-address 10.20.20.10;
next-server 172.16.6.129;
ddns-updates off;
option time-servers 172.16.6.129;
option PC-MTA.Provision-server 1 172.16.6.129;
#option PC-MTA.Provision-server 05:30:20:6e:65:74:75:6e:6f:01:6e:65:74:00;
#option PC-MTA.Provision-server 0 05:6E:65:74:75:6E:6F:01:31:00;
#option PC-MTA.AS-REQ_AS-REP 100 100000 20;
#option PC-MTA.AP-REQ_AP-REP 100 100000 20;
option PC-MTA.Kerberos-realm 05:42:41:53:49:43:01:31:00;
#option PC-MTA.Kerberos-realm "\005BASIC\0011\000";
#option PC-MTA.TGS-util 200;
#option PC-MTA.Provision-timer 255;
#option PC-MTA.Ticket-ctrl-mask 255;
}

frnkblk
Please make available a

Please make available a packet capture of the exchange between your eMTA and your DHCP server. That should make it much more clear what's actually going on.

Frank

hrguille (not verified)
Cature from ethereal readed with tcpdump + syslog

Hey Frank, here are the syslog info and the ethereal file readed bay tcpdump. The option 122 subotions are not well pictured but Iñm sending 122.3 and 122.6.

I really appreciate your help.

ab3-ing:~# !tail
tail -f /var/log/syslog
Jan 22 11:46:47 lab3-ing dhcpd: DHCPDISCOVER from 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:46:47 lab3-ing dhcpd: DHCPOFFER on 10.20.20.10 to 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:46:55 lab3-ing dhcpd: DHCPDISCOVER from 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:46:55 lab3-ing dhcpd: DHCPOFFER on 10.20.20.10 to 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:47:11 lab3-ing dhcpd: DHCPDISCOVER from 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:47:11 lab3-ing dhcpd: DHCPOFFER on 10.20.20.10 to 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:47:52 lab3-ing dhcpd: DHCPDISCOVER from 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:47:52 lab3-ing dhcpd: DHCPOFFER on 10.20.20.10 to 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:47:56 lab3-ing dhcpd: DHCPDISCOVER from 00:0f:21:79:d7:76 via 10.20.20.1
Jan 22 11:47:56 lab3-ing dhcpd: DHCPOFFER on 10.20.20.10 to 00:0f:21:79:d7:76 via 10.20.20.1

*****************************************************************************************************************

lab3-ing:~# tcpdump -v -r captura_docsis2.0_220108_11am
reading from file captura_docsis2.0_220108_11am, link-type EN10MB (Ethernet)
11:08:09.857385 IP (tos 0x0, ttl 64, id 28615, offset 0, flags [DF], length: 60) urb-2-130.net-uno.net.3088 > urb-2-41.net-uno.net.bacula-sd: S [tcp sum ok] 674928352:674928352(0) win 5840
11:08:11.857077 arp who-has urb-2-129.net-uno.net tell urb-2-130.net-uno.net
11:08:11.857135 arp reply urb-2-129.net-uno.net is-at 00:06:4f:11:92:19
11:08:15.662666 00:0b:5f:c8:c9:ad > 00:0b:5f:c8:c9:ad, ethertype Loopback (0x9000), length 60:
0x0000: 0000 0100 0000 0000 0000 0000 0000 0000 ................
0x0010: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0020: 0000 0000 0000 0000 0000 0000 0000 ..............
11:08:15.856516 IP (tos 0x0, ttl 64, id 28616, offset 0, flags [DF], length: 60) urb-2-130.net-uno.net.3088 > urb-2-41.net-uno.net.bacula-sd: S [tcp sum ok] 674928352:674928352(0) win 5840
11:08:23.317375 IP (tos 0x0, ttl 255, id 8234, offset 0, flags [none], length: 432) 10.10.10.1.bootps > urb-2-129.net-uno.net.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:0f:21:79:d7:74, length: 404, hops:1, xid:0x7ac9, flags: [none]
Gateway IP: 10.10.10.1
Client Ethernet Address: 00:0f:21:79:d7:74
Vendor-rfc1048:
DHCP:DISCOVER
PR:SM+TZ+DG+TS+LOG+NS+TFTP+BF+PAD+PAD+PAD+T122+PAD+PAD+PAD+T177
VC:"docsis1.0"
VO:2.3.69.67.77.3.8.69.67.77.58.69.77.84.65.4.9.49.48.51.52.55.56.51.48.57.5.3.49.46.49.6.16.118.49.46.48.46.49.114.49.49.51.51.45.48.53.49.51.7.6.50.46.49.46.54.98.8.6.48.48.48.102.50.49.9.7.68.80.88.50.50.48.51.10.3.83.45.65.200.3.83.45.65.201.7.68.80.88.50.50.48.51.202.16.118.49.46.48.46.49.114.49.49.51.51.45.48.53.49.51.203.3.49.46.49
CID:[ether]00:0f:21:79:d7:74
MSZ:1500
11:08:23.318171 IP (tos 0x0, ttl 64, id 2, offset 0, flags [DF], length: 357) urb-2-129.net-uno.net.bootps > 10.10.10.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 329, hops:1, xid:0x7ac9, flags: [none]
Your IP: 10.10.10.4
Server IP: urb-2-129.net-uno.net
Gateway IP: 10.10.10.1
Client Ethernet Address: 00:0f:21:79:d7:74
Vendor-rfc1048:
DHCP:OFFER
SID:urb-2-129.net-uno.net
LT:600
SM:255.255.255.0
TZ:10800
DG:10.10.10.1
LOG:urb-2-129.net-uno.net
NS:urb-2-129.net-uno.net
TFTP:"172.16.6.129"
BF:"1-1-1-1-1.bin"
T122:17083408,109117956,2886731393
11:08:25.397305 IP (tos 0x0, ttl 255, id 8236, offset 0, flags [none], length: 444) 10.10.10.1.bootps > urb-2-129.net-uno.net.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:0f:21:79:d7:74, length: 416, hops:1, xid:0x7ac9, secs:2, flags: [none]
Gateway IP: 10.10.10.1
Client Ethernet Address: 00:0f:21:79:d7:74
Vendor-rfc1048:
DHCP:REQUEST
PR:SM+TZ+DG+TS+LOG+NS+TFTP+BF+PAD+PAD+PAD+T122+PAD+PAD+PAD+T177
VC:"docsis1.0"
VO:2.3.69.67.77.3.8.69.67.77.58.69.77.84.65.4.9.49.48.51.52.55.56.51.48.57.5.3.49.46.49.6.16.118.49.46.48.46.49.114.49.49.51.51.45.48.53.49.51.7.6.50.46.49.46.54.98.8.6.48.48.48.102.50.49.9.7.68.80.88.50.50.48.51.10.3.83.45.65.200.3.83.45.65.201.7.68.80.88.50.50.48.51.202.16.118.49.46.48.46.49.114.49.49.51.51.45.48.53.49.51.203.3.49.46.49
CID:[ether]00:0f:21:79:d7:74
RQ:10.10.10.4
SID:urb-2-129.net-uno.net
MSZ:1500
11:08:25.398186 IP (tos 0x0, ttl 64, id 3, offset 0, flags [DF], length: 357) urb-2-129.net-uno.net.bootps > 10.10.10.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 329, hops:1, xid:0x7ac9, secs:2, flags: [none]
Your IP: 10.10.10.4
Server IP: urb-2-129.net-uno.net
Gateway IP: 10.10.10.1
Client Ethernet Address: 00:0f:21:79:d7:74
Vendor-rfc1048:
DHCP:ACK
SID:urb-2-129.net-uno.net
LT:600
SM:255.255.255.0
TZ:10800
DG:10.10.10.1
LOG:urb-2-129.net-uno.net
NS:urb-2-129.net-uno.net
TFTP:"172.16.6.129"
BF:"1-1-1-1-1.bin"
T122:17083408,109117956,2886731393
11:08:25.658183 CDPv2, ttl: 180s, checksum: 692 (unverified), length 394
Device-ID (0x01), length: 15 bytes: 'CAT3550-LAB-ING'
Address (0x02), length: 13 bytes: IPv4 (1) urb-2-6.net-uno.net
Port-ID (0x03), length: 16 bytes: 'FastEthernet0/45'
Capability (0x04), length: 4 bytes: (0x00000028): L2 Switch, IGMP snooping
Version String (0x05), length: 217 bytes:
Cisco Internetwork Operating System Software
IOS (tm) C3550 Software (C3550-I5Q3L2-M), Version 12.1(22)EA6, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2005 by cisco Systems, Inc.
Compiled Fri 21-Oct-05 02:16 by yenanh
Platform (0x06), length: 17 bytes: 'cisco WS-C3550-48'
Protocol-Hello option (0x08), length: 32 bytes:
VTP Management Domain (0x09), length: 6 bytes: 'netuno'
Native VLAN ID (0x0a), length: 2 bytes: 500
Duplex (0x0b), length: 1 byte: full
AVVID trust bitmap (0x12), length: 1 byte: 0x00
AVVID untrusted ports CoS (0x13), length: 1 byte: 0x00
Management Addresses (0x16), length: 13 bytes: IPv4 (1) urb-2-6.net-uno.net
11:08:25.663787 00:0b:5f:c8:c9:ad > 01:00:0c:cc:cc:cc snap ui/C len=35
11:08:25.663888 00:0b:5f:c8:c9:ad > 01:00:0c:00:00:00 snap ui/C len=65
11:08:25.669089 00:0b:5f:c8:c9:ad > 00:0b:5f:c8:c9:ad, ethertype Loopback (0x9000), length 60:
0x0000: 0000 0100 0000 0000 0000 0000 0000 0000 ................
0x0010: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0020: 0000 0000 0000 0000 0000 0000 0000 ..............
11:08:26.578719 IP (tos 0x0, ttl 63, id 13, offset 0, flags [none], length: 50) 10.10.10.4.1030 > urb-2-129.net-uno.net.tftp: [udp sum ok] 22 RRQ "1-1-1-1-1.bin" octet
11:08:26.594974 IP (tos 0x0, ttl 64, id 6, offset 0, flags [DF], length: 112) urb-2-129.net-uno.net.tftp > 10.10.10.4.1030: [udp sum ok] 84 DATA block 1
11:08:26.622650 IP (tos 0x0, ttl 63, id 15, offset 0, flags [none], length: 32) 10.10.10.4.1030 > urb-2-129.net-uno.net.tftp: [udp sum ok] 4 ACK block 1
11:08:27.854825 IP (tos 0x0, ttl 64, id 28617, offset 0, flags [DF], length: 60) urb-2-130.net-uno.net.3088 > urb-2-41.net-uno.net.bacula-sd: S [tcp sum ok] 674928352:674928352(0) win 5840
11:08:28.316872 arp who-has urb-2-146.net-uno.net tell urb-2-129.net-uno.net
11:08:28.317537 arp reply urb-2-146.net-uno.net is-at 00:1b:8f:ee:58:02
11:08:28.675254 IP (tos 0x0, ttl 255, id 8238, offset 0, flags [none], length: 367) 10.20.20.1.bootps > urb-2-129.net-uno.net.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:0f:21:79:d7:76, length: 339, hops:1, xid:0x7aca, flags: [none]
Gateway IP: 10.20.20.1
Client Ethernet Address: 00:0f:21:79:d7:76
Vendor-rfc1048:
DHCP:DISCOVER
PR:SM+TZ+DG+NS+LOG+HN+DN+SID+T122+T177
VC:"pktc1.0:051c0101000201020901010b0506090305040c01010d01010f0101100109"
CID:[ether]00:0f:21:79:d7:76
MSZ:1500
11:08:28.676106 IP (tos 0x0, ttl 64, id 4, offset 0, flags [DF], length: 354) urb-2-129.net-uno.net.bootps > 10.20.20.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 326, hops:1, xid:0x7aca, flags: [none]
Your IP: 10.20.20.10
Server IP: urb-2-129.net-uno.net
Gateway IP: 10.20.20.1
Client Ethernet Address: 00:0f:21:79:d7:76
file "mta.bin"
Vendor-rfc1048:
DHCP:OFFER
SID:urb-2-129.net-uno.net
LT:600
SM:255.255.255.0
TZ:10800
DG:10.20.20.1
NS:urb-2-129.net-uno.net
LOG:urb-2-129.net-uno.net
HN:"emta1"
DN:"net-uno.net"
T122:773,428,4102,33030,2309,16961,21321,17153,12544
11:08:33.673319 IP (tos 0x0, ttl 255, id 8240, offset 0, flags [none], length: 367) 10.20.20.1.bootps > urb-2-129.net-uno.net.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:0f:21:79:d7:76, length: 339, hops:1, xid:0x7acb, secs:5, flags: [none]
Gateway IP: 10.20.20.1
Client Ethernet Address: 00:0f:21:79:d7:76
Vendor-rfc1048:
DHCP:DISCOVER
PR:SM+TZ+DG+NS+LOG+HN+DN+SID+T122+T177
VC:"pktc1.0:051c0101000201020901010b0506090305040c01010d01010f0101100109"
CID:[ether]00:0f:21:79:d7:76
MSZ:1500
11:08:33.674052 IP (tos 0x0, ttl 64, id 5, offset 0, flags [DF], length: 354) urb-2-129.net-uno.net.bootps > 10.20.20.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 326, hops:1, xid:0x7acb, secs:5, flags: [none]
Your IP: 10.20.20.10
Server IP: urb-2-129.net-uno.net
Gateway IP: 10.20.20.1
Client Ethernet Address: 00:0f:21:79:d7:76
file "mta.bin"
Vendor-rfc1048:
DHCP:OFFER
SID:urb-2-129.net-uno.net
LT:600
SM:255.255.255.0
TZ:10800
DG:10.20.20.1
NS:urb-2-129.net-uno.net
LOG:urb-2-129.net-uno.net
HN:"emta1"
DN:"net-uno.net"
T122:773,428,4102,33030,2309,16961,21321,17153,12544
11:08:35.667466 00:0b:5f:c8:c9:ad > 00:0b:5f:c8:c9:ad, ethertype Loopback (0x9000), length 60:
0x0000: 0000 0100 0000 0000 0000 0000 0000 0000 ................
0x0010: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0020: 0000 0000 0000 0000 0000 0000 0000 ..............
11:08:42.673238 IP (tos 0x0, ttl 255, id 8242, offset 0, flags [none], length: 367) 10.20.20.1.bootps > urb-2-129.net-uno.net.bootps: [udp sum ok] BOOTP/DHCP, Request from 00:0f:21:79:d7:76, length: 339, hops:1, xid:0x7acc, secs:14, flags: [none]
Gateway IP: 10.20.20.1
Client Ethernet Address: 00:0f:21:79:d7:76
Vendor-rfc1048:
DHCP:DISCOVER
PR:SM+TZ+DG+NS+LOG+HN+DN+SID+T122+T177
VC:"pktc1.0:051c0101000201020901010b0506090305040c01010d01010f0101100109"
CID:[ether]00:0f:21:79:d7:76
MSZ:1500
11:08:42.673975 IP (tos 0x0, ttl 64, id 6, offset 0, flags [DF], length: 354) urb-2-129.net-uno.net.bootps > 10.20.20.1.bootps: [udp sum ok] BOOTP/DHCP, Reply, length: 326, hops:1, xid:0x7acc, secs:14, flags: [none]
Your IP: 10.20.20.10
Server IP: urb-2-129.net-uno.net
Gateway IP: 10.20.20.1
Client Ethernet Address: 00:0f:21:79:d7:76
file "mta.bin"
Vendor-rfc1048:
DHCP:OFFER
SID:urb-2-129.net-uno.net
LT:600
SM:255.255.255.0
TZ:10800
DG:10.20.20.1
NS:urb-2-129.net-uno.net
LOG:urb-2-129.net-uno.net
HN:"emta1"
DN:"net-uno.net"
T122:773,428,4102,33030,2309,16961,21321,17153,12544
11:08:45.667861 00:0b:5f:c8:c9:ad > 00:0b:5f:c8:c9:ad, ethertype Loopback (0x9000), length 60:
0x0000: 0000 0100 0000 0000 0000 0000 0000 0000 ................
0x0010: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0x0020: 0000 0000 0000 0000 0000 0000 0000 ..............
lab3-ing:~#

hinzoo
Not analyzing: soft version

Not analyzing: soft version on modem or routing problem or ToD problem or wrong VendorSpecific OUI

scramatte
I've got the same problem with an arris c3/mta

Hello

I've got the same problem with an arris c3/mta
We have goy an Arris C3 CMTS setup as router + dhcp relay and we use separate interface for modem and cpe
on both side (cable and fast ethernet)

When I try to provisioning a mta the CM is registered corectly with the CMTS
MTA send a dhcp dicover to my DHCP server and this one send a DHCP Offer ...

For any reason the DHCPACK never occur and MTA go into discover-offer loop

I've you got any tips ? Have you resolve this issue ?

Regards

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