12> kernel: AdslCoreEcUpdTmr: timeMs=1800075 ecUpdMask=0x40000
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=124.104.66.37 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x00 TTL=119 ID=47200 DF PROTO=TCP SPT=3951 DPT=445 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=124.104.66.37 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x00 TTL=119 ID=47287 DF PROTO=TCP SPT=3951 DPT=445 WINDOW=65535 RES=0x00 SYN URGP=0
12> dnsprobe[468]: dns query failed
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=186.100.204.54 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x20 TTL=105 ID=22392 DF PROTO=TCP SPT=1563 DPT=445 WINDOW=16384 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=186.100.204.54 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x20 TTL=105 ID=22480 DF PROTO=TCP SPT=1563 DPT=445 WINDOW=16384 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=112.202.105.163 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x00 TTL=118 ID=14757 DF PROTO=TCP SPT=3976 DPT=445 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=81.36.95.184 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x20 TTL=112 ID=55478 DF PROTO=TCP SPT=4286 DPT=445 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=61.101.176.159 DST=77.40.14.10 LEN=48 TOS=0x00 PREC=0x00 TTL=117 ID=10303 DF PROTO=TCP SPT=2214 DPT=445 WINDOW=65535 RES=0x00 SYN URGP=0
26> pppd[274]: Clear IP addresses. Connection DOWN.
26> pppd[274]: Clear IP addresses. PPP connection DOWN.
29> pppd[274]: PPP: Start to connect ...
26> pppd[274]: PPP server detected.
26> pppd[274]: PPP session established.
29> pppd[274]: PPP: Start to connect ...
30> pppd[274]: Exit.
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
13> dnsprobe[468]: Primary DNS server Is Down... Switching To Secondary DNS server
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
46> -- MARK --
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
46> -- MARK --
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
12> dnsprobe[468]: dns query failed
Прошивка 1.51, пробовал 1.40 патченую реконектит нормально но как то напрягает. Сейчас стоит huawei 880 3 дня не одного падения. Делинк максимум часов 12 держит сессию. DSLAM huawei.

Попробуйте следующее:
Установите эту прошивку: ftp://ftp.dlink.ru/pub/ADSL/DSL-2500U_B ... _fs_kernel

Под опцией Keep-Alive появится возможность задать значение LCP echo interval.
Увеличьте это значение, к примеру, до минуты (значение по умолчанию: 30 секунд).

12> kernel: AnnexCParam=0x7FFF7EB8 AnnexAParam=0x00001980 adsl2=0x00000000
12> kernel: pSdramPHY=0xA07FFFF8, 0x1B785D 0xDEADBEEF
12> kernel: AdslCoreHwReset: AdslOemDataAddr = 0xA07EF96C
12> kernel: AnnexCParam=0x7FFF7EB8 AnnexAParam=0x00001980 adsl2=0x00000000
12> kernel: dgasp: kerSysRegisterDyingGaspHandler: dsl0 registered
12> kernel: ATM proc init !!!
10> kernel: ADSL G.994 training
12> kernel: ip_tables: (C) 2000-2002 Netfilter core team
12> kernel: ip_conntrack version 2.1 (61 buckets, 0 max) - 376 bytes per conntrack
12> kernel: ip_conntrack_pptp version 2.1 loaded
12> kernel: ip_nat_pptp version 2.0 loaded
12> kernel: unregistering helper for port 5060
12> kernel: unregistering helper for port 5060
10> kernel: ADSL G.992 started
14> kernel: device eth0 entered promiscuous mode
14> kernel: br0: port 1(eth0) entering learning state
14> kernel: br0: topology change detected, propagating
14> kernel: br0: port 1(eth0) entering forwarding state
15> syslog: echo > /var/snmpd.conf
10> kernel: ADSL G.992 channel analysis
15> syslog: pppd -c 0.0.33.1 -i nas_0_0_33 -u login -p ******* -f 3 -k -m 00188230d2f0/1663 &
29> pppd[283]: pppd 2.4.1 started by admin, uid 0
10> kernel: ADSL G.992 message exchange
10> kernel: ADSL link up, interleaved, us=1023, ds=6143
12> kernel: ADSL2/ADSL2+ connection
12> kernel: ATM Soft SAR: ATM link connected.
15> syslog: iptables -t nat -A PREROUTING -i br0 -d 192.168.0.99 -p udp --dport 53 -j DNAT --to 128.9.0.107
29> pppd[283]: PPP: Start to connect ...
26> pppd[283]: PPP server detected.
29> pppd[283]: PPP: Start to connect ...
26> pppd[283]: PPP server detected.
26> pppd[283]: PPP session established.
26> pppd[283]: PPP LCP UP.
26> pppd[283]: Received valid IP address from server. Connection UP.
15> syslog: route add default gw 192.168.65.200 2>/dev/null
15> syslog: iptables -A FORWARD -o ppp_0_0_33_1 -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
15> syslog: iptables -A FORWARD -i ppp_0_0_33_1 -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
15> syslog: echo > /proc/net/ip_conntrack
15> syslog: echo "600" > /proc/sys/net/ipv4/ip_conntrack_max
15> syslog: echo 2000 > /proc/sys/net/ipv4/netfilter/ip_conntrack_generic_timeout
15> syslog: echo 600 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_established
15> syslog: echo 1400 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_fin_wait
15> syslog: echo 2000 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_timeout_time_wait
15> syslog: echo 4096 > /proc/sys/net/ipv4/ipfrag_high_thresh
15> syslog: echo 1024 > /proc/sys/net/ipv4/ipfrag_low_thresh
15> syslog: echo 5 > /proc/sys/net/ipv4/ipfrag_time
15> syslog: iptables -t nat -D PREROUTING -i br0 -d 192.168.0.99 -p udp --dport 53 -j DNAT --to 128.9.0.107 2>/dev/null
15> syslog: iptables -t nat -D POSTROUTING -o ppp_0_0_33_1 -s 192.168.0.0/255.255.255.0 -j MASQUERADE 2>/dev/null
15> syslog: iptables -t nat -A POSTROUTING -o ppp_0_0_33_1 -s 192.168.0.0/255.255.255.0 -j MASQUERADE
15> syslog: iptables -t nat -D PREROUTING -i br0 -d 192.168.0.99 -p udp --dport 53 -j DNAT --to 77.40.0.2 2>/dev/null
15> syslog: iptables -t nat -A PREROUTING -i br0 -d 192.168.0.99 -p udp --dport 53 -j DNAT --to 77.40.0.2
15> syslog: /bin/dnsprobe &
13> dnsprobe[483]: dnsprobe started!
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=213.220.235.54 DST=77.40.37.154 LEN=64 TOS=0x00 PREC=0x00 TTL=52 ID=49037 DF PROTO=TCP SPT=62810 DPT=43062 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=213.220.235.54 DST=77.40.37.154 LEN=64 TOS=0x00 PREC=0x00 TTL=52 ID=34963 DF PROTO=TCP SPT=62810 DPT=43062 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=213.220.235.54 DST=77.40.37.154 LEN=64 TOS=0x00 PREC=0x00 TTL=52 ID=38798 DF PROTO=TCP SPT=62810 DPT=43062 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=213.220.235.54 DST=77.40.37.154 LEN=48 TOS=0x00 PREC=0x00 TTL=52 ID=47058 DF PROTO=TCP SPT=62810 DPT=43062 WINDOW=65535 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=213.220.235.54 DST=77.40.37.154 LEN=48 TOS=0x00 PREC=0x00 TTL=52 ID=31462 DF PROTO=TCP SPT=62810 DPT=43062 WINDOW=65535 RES=0x00 SYN URGP=0
13> igmp[209]: setsockopt IP_MSFILTER
13> igmp[209]: setsockopt IP_MSFILTER
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=88.130.74.178 DST=77.40.37.154 LEN=48 TOS=0x00 PREC=0x20 TTL=53 ID=15813 DF PROTO=TCP SPT=4791 DPT=43062 WINDOW=32768 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=210.193.13.104 DST=77.40.37.154 LEN=48 TOS=0x00 PREC=0x00 TTL=115 ID=13169 DF PROTO=TCP SPT=54388 DPT=4899 WINDOW=16384 RES=0x00 SYN URGP=0
9> kernel: Intrusion -> IN=ppp_0_0_33_1 OUT= MAC= SRC=94.51.72.235 DST=77.40.37.154 LEN=48 TOS=0x00 PREC=0x20 TTL=117 ID=56519 DF PROTO=TCP SPT=1711 DPT=11763 WINDOW=65535 RES=0x00 SYN URGP=0
12> dnsprobe[483]: dns query failed
12> dnsprobe[483]: dns query failed
12> dnsprobe[483]: dns query failed
13> dnsprobe[483]: Primary DNS server Is Down... Switching To Secondary DNS server