Всем привет.
Я работаю в технической поддержке провайдера.
Помогите разобраться, кто виноват.
К нам поступают постоянные жалобы на разрывы PPPoE сессий от клиентов с модемами серии DSL-2500U/BRU/D (сюда же попадает и модем 2520). Если настроить модем в режим моста, то проблема исчезает.
У нас имеется:
1. IPDSLAM DAS-3248 Rev. B1 (прошивки на всех разные от самой новой до самой бородатой, это ситуацию не меняет)
2. BRAS FreeBSD 7.1 MPD 4.4.1_1
3. Различные модемы, см. выше. По статистике жалоб можно понять, что в основном это вышеуказанные модемы. Смена прошивки не помогала.
По статистике сессия длится около 5 минут. Дальше идет разрыв из-за превышения времени ожидания LCP echo-request. Причем так "думает" и BRAS и сам модем. Но при просмотре вывода утилиты tcpdump выясняется, что на все полученные echo-request BRAS отправил модему echo-reply, и напротив - модем не отвечает на echo-request, чем дальше тем чаще пока не происходит разрыв.
00:1c:f0:29:9b:1b - это MAC модема.
Код:
unlimit# tcpdump -pvvvns0 -e -i vlan4 ether host 00:1c:f0:29:9b:1b
tcpdump: WARNING: vlan4: no IPv4 address assigned
tcpdump: listening on vlan4, link-type EN10MB (Ethernet), capture size 65535 bytes
09:55:57.424524 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 7, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0907 0008
Magic-Num 0x36dd395c
09:55:57.456523 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 7, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a07 0008
Magic-Num 0x7f0634ad
09:56:16.823527 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 6, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0906 0008
Magic-Num 0x7f0634ad
09:56:16.824506 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 6, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a06 0008
Magic-Num 0x36dd395c
09:56:27.486643 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 8, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0908 0008
Magic-Num 0x36dd395c
09:56:32.787943 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 70: PPPoE [ses 0xc5cc] IP (0x0021), length 50: (tos 0x0, ttl 116, id 2759, offset 0, flags [DF], proto TCP (6), length 48) 91.202.88.188.4694 > 91.202.95.168.135: S, cksum 0x0bb5 (correct), 2602065007:2602065007(0) win 64800 <mss 1440,nop,nop,sackOK>
09:56:37.487786 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 9, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0909 0008
Magic-Num 0x36dd395c
09:56:46.823662 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 7, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0907 0008
Magic-Num 0x7f0634ad
09:56:46.824643 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 7, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a07 0008
Magic-Num 0x36dd395c
09:56:57.489660 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 10, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090a 0008
Magic-Num 0x36dd395c
09:57:07.491227 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 11, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090b 0008
Magic-Num 0x36dd395c
09:57:16.822217 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 8, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0908 0008
Magic-Num 0x7f0634ad
09:57:16.843122 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 8, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a08 0008
Magic-Num 0x36dd395c
09:57:27.492952 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 12, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090c 0008
Magic-Num 0x36dd395c
09:57:37.495633 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 13, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090d 0008
Magic-Num 0x36dd395c
09:57:46.821751 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 9, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0909 0008
Magic-Num 0x7f0634ad
09:57:46.822695 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 9, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a09 0008
Magic-Num 0x36dd395c
09:57:57.496474 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 14, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090e 0008
Magic-Num 0x36dd395c
09:58:07.497582 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 15, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090f 0008
Magic-Num 0x36dd395c
09:58:16.819296 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 10, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090a 0008
Magic-Num 0x7f0634ad
09:58:16.820256 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 10, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a0a 0008
Magic-Num 0x36dd395c
09:58:27.500081 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 16, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0910 0008
Magic-Num 0x36dd395c
09:58:37.502773 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 17, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0911 0008
Magic-Num 0x36dd395c
09:58:46.817005 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 11, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 090b 0008
Magic-Num 0x7f0634ad
09:58:46.817958 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Reply (0x0a), id 11, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0a0b 0008
Magic-Num 0x36dd395c
09:58:57.505282 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 18, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0912 0008
Magic-Num 0x36dd395c
09:59:07.506464 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 30: PPPoE [ses 0xc5cc] LCP (0xc021), length 10: LCP, Echo-Request (0x09), id 19, length 10
encoded length 8 (=Option(s) length 4)
0x0000: c021 0913 0008
Magic-Num 0x36dd395c
09:59:07.961578 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 86: PPPoE [ses 0xc5cc] IP (0x0021), length 66: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 64) 91.202.95.168.3073 > 192.168.100.3.53: [udp sum ok] 1234+ A? a.root-servers.net. (36)
09:59:07.963555 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 102: PPPoE [ses 0xc5cc] IP (0x0021), length 82: (tos 0x0, ttl 126, id 916, offset 0, flags [none], proto UDP (17), length 80) 192.168.100.3.53 > 91.202.95.168.3073: [udp sum ok] 1234 q: A? a.root-servers.net. 1/0/0 a.root-servers.net. A 198.41.0.4 (52)
09:59:08.345485 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 234: PPPoE [ses 0xc5cc] IP (0x0021), length 214: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 212) 91.202.95.168 > 91.202.95.1: ICMP echo request, id 0, seq 0, length 192
09:59:08.345510 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 234: PPPoE [ses 0xc5cc] IP (0x0021), length 214: (tos 0x0, ttl 64, id 56600, offset 0, flags [DF], proto ICMP (1), length 212) 91.202.95.1 > 91.202.95.168: ICMP echo reply, id 0, seq 0, length 192
09:59:09.973461 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 86: PPPoE [ses 0xc5cc] IP (0x0021), length 66: (tos 0x0, ttl 64, id 1, offset 0, flags [DF], proto UDP (17), length 64) 91.202.95.168.3073 > 192.168.100.3.53: [udp sum ok] 1234+ A? a.root-servers.net. (36)
09:59:09.974548 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 102: PPPoE [ses 0xc5cc] IP (0x0021), length 82: (tos 0x0, ttl 126, id 1089, offset 0, flags [none], proto UDP (17), length 80) 192.168.100.3.53 > 91.202.95.168.3073: [udp sum ok] 1234 q: A? a.root-servers.net. 1/0/0 a.root-servers.net. A 198.41.0.4 (52)
09:59:11.983429 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 86: PPPoE [ses 0xc5cc] IP (0x0021), length 66: (tos 0x0, ttl 64, id 2, offset 0, flags [DF], proto UDP (17), length 64) 91.202.95.168.3073 > 192.168.100.3.53: [udp sum ok] 1234+ A? a.root-servers.net. (36)
09:59:11.983912 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 102: PPPoE [ses 0xc5cc] IP (0x0021), length 82: (tos 0x0, ttl 126, id 1430, offset 0, flags [none], proto UDP (17), length 80) 192.168.100.3.53 > 91.202.95.168.3073: [udp sum ok] 1234 q: A? a.root-servers.net. 1/0/0 a.root-servers.net. A 198.41.0.4 (52)
09:59:13.388444 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 234: PPPoE [ses 0xc5cc] IP (0x0021), length 214: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 212) 91.202.95.168 > 192.168.100.3: ICMP echo request, id 0, seq 0, length 192
09:59:13.389527 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 234: PPPoE [ses 0xc5cc] IP (0x0021), length 214: (tos 0x0, ttl 126, id 1573, offset 0, flags [DF], proto ICMP (1), length 212) 192.168.100.3 > 91.202.95.168: ICMP echo reply, id 0, seq 0, length 192
09:59:16.824360 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 25: LCP, Term-Request (0x05), id 113, length 25
encoded length 23 (=Option(s) length 19)
0x0000: c021 0571 0017
09:59:17.006665 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE S (0x8864), length 26: PPPoE [ses 0xc5cc] LCP (0xc021), length 6: LCP, Term-Ack (0x06), id 187, length 6
09:59:19.010409 00:30:05:76:0f:b7 > 00:1c:f0:29:9b:1b, ethertype PPPoE D (0x8863), length 38: PPPoE PADT [ses 0xc5cc] [Generic-Error "session closed"]
09:59:19.821310 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE S (0x8864), length 56: PPPoE [ses 0xc5cc] LCP (0xc021), length 25: LCP, Term-Request (0x05), id 114, length 25
encoded length 23 (=Option(s) length 19)
0x0000: c021 0572 0017
09:59:22.852445 00:1c:f0:29:9b:1b > 00:30:05:76:0f:b7, ethertype PPPoE D (0x8863), length 56: PPPoE PADT [ses 0xc5cc] [Host-Uniq 0x10046100] [Service-Name]
^C
42 packets captured
237435 packets received by filter
0 packets dropped by kernel
В момент, когда начинают теряться echo-request, ATM loopback тесты на порту этого модема уже не проходят.
В логах модема:
Код:
Jul 23 10:06:59 daemon crit pppd[289]: PPP server detected.
Jul 23 10:07:02 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:07:02 daemon crit pppd[289]: PPP server detected.
Jul 23 10:07:02 daemon crit pppd[289]: PPP session established.
Jul 23 10:07:04 daemon crit pppd[289]: PPP LCP UP.
Jul 23 10:07:04 daemon crit pppd[289]: Received valid IP address from server. Connection UP.
Jul 23 10:07:04 user debug syslog: route add default gw 91.202.95.1 2>/dev/null
Jul 23 10:07:05 user debug syslog: iptables -A FORWARD -o ppp_0_8_35_1 -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
Jul 23 10:07:05 user debug syslog: iptables -A FORWARD -i ppp_0_8_35_1 -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
Jul 23 10:07:05 user debug syslog: iptables -t nat -D POSTROUTING -o ppp_0_8_35_1 -s 192.168.1.0/255.255.255.0 -j MASQUERADE 2>/dev/null
Jul 23 10:07:05 user debug syslog: iptables -t nat -A POSTROUTING -o ppp_0_8_35_1 -s 192.168.1.0/255.255.255.0 -j MASQUERADE
Jul 23 10:08:29 user alert kernel: Intrusion -> IN=ppp_0_8_35_1 OUT= MAC= SRC=89.178.26.149 DST=91.202.95.228 LEN=60 TOS=0x00 PREC=0x00 TTL=55 ID=42553 DF PROTO=TCP SPT=59342 DPT=18898 WINDOW=5840 RES=0x00 SYN URGP=0
Jul 23 10:08:32 user alert kernel: Intrusion -> IN=ppp_0_8_35_1 OUT= MAC= SRC=89.178.26.149 DST=91.202.95.228 LEN=60 TOS=0x00 PREC=0x00 TTL=55 ID=58541 DF PROTO=TCP SPT=59342 DPT=18898 WINDOW=5840 RES=0x00 SYN URGP=0
Jul 23 10:10:10 user warn dnsprobe[549]: dns query failed
Jul 23 10:10:12 user warn dnsprobe[549]: dns query failed
Jul 23 10:10:14 user warn dnsprobe[549]: dns query failed
Jul 23 10:12:04 daemon crit pppd[289]: Clear IP addresses. Connection DOWN.
Jul 23 10:12:04 daemon crit pppd[289]: Clear IP addresses. PPP connection DOWN.
Jul 23 10:12:13 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:16 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:19 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:22 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:25 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:28 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:31 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:34 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:37 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:37 daemon crit pppd[289]: PPP server detected.
Jul 23 10:12:40 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:41 daemon crit pppd[289]: PPP server detected.
Jul 23 10:12:44 daemon notice pppd[289]: PPP: Start to connect ...
Jul 23 10:12:44 daemon crit pppd[289]: PPP server detected.
Jul 23 10:12:44 daemon crit pppd[289]: PPP session established.
Jul 23 10:12:46 daemon crit pppd[289]: PPP LCP UP.
Jul 23 10:12:46 daemon crit pppd[289]: Received valid IP address from server. Connection UP.
Jul 23 10:12:46 user debug syslog: route add default gw 91.202.95.1 2>/dev/null
Jul 23 10:12:46 user debug syslog: iptables -A FORWARD -o ppp_0_8_35_1 -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
Jul 23 10:12:46 user debug syslog: iptables -A FORWARD -i ppp_0_8_35_1 -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
Jul 23 10:12:46 user debug syslog: iptables -t nat -D POSTROUTING -o ppp_0_8_35_1 -s 192.168.1.0/255.255.255.0 -j MASQUERADE 2>/dev/null
Jul 23 10:12:46 user debug syslog: iptables -t nat -A POSTROUTING -o ppp_0_8_35_1 -s 192.168.1.0/255.255.255.0 -j MASQUERADE
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