conexão virtua cai toda hora

Galera!

Muita boa tarde, estou com um problema que ainda não sei como resolver.

Minha conexão virtua cai toda hora, e depois de algumas hora verificando os log, percebi que após algumas tentativas de acesso não autorizados o linnk cai, e tenho que reiniciar o micro.

segue abaixo parte do syslog

Oct 18 12:59:37 localhost sshd[2016]: Connection from 211.157.97.11 port 40763
Oct 18 12:59:41 localhost sshd[2016]: Illegal user guest from 211.157.97.11
Oct 18 12:59:42 localhost sshd[2018]: Connection from 211.157.97.11 port 40840
Oct 18 12:59:45 localhost sshd[2018]: Illegal user admin from 211.157.97.11
Oct 18 12:59:46 localhost sshd[2020]: Connection from 211.157.97.11 port 40919
Oct 18 12:59:50 localhost sshd[2020]: Illegal user admin from 211.157.97.11
Oct 18 12:59:51 localhost sshd[2022]: Connection from 211.157.97.11 port 40996
Oct 18 12:59:55 localhost sshd[2022]: Illegal user user from 211.157.97.11
Oct 18 12:59:56 localhost sshd[2024]: Connection from 211.157.97.11 port 41084
Oct 18 13:00:00 localhost sshd[2024]: User root not allowed because none of user's groups are listed in AllowGroups
Oct 18 13:00:01 localhost sshd[2026]: Connection from 211.157.97.11 port 41173
Oct 18 13:00:05 localhost sshd[2026]: User root not allowed because none of user's groups are listed in AllowGroups
Oct 18 13:00:06 localhost sshd[2028]: Connection from 211.157.97.11 port 41264
Oct 18 13:00:10 localhost sshd[2028]: User root not allowed because none of user's groups are listed in AllowGroups
Oct 18 13:00:11 localhost sshd[2030]: Connection from 211.157.97.11 port 41345
Oct 18 13:00:15 localhost sshd[2030]: Illegal user test from 211.157.97.11
Oct 18 13:02:26 localhost named[1611]: Cleaned cache of 210 RRsets
Oct 18 13:02:26 localhost named[1611]: USAGE 1161183746 1161180146 CPU=0.22u/0.09s CHILDCPU=0u/0s
Oct 18 13:02:26 localhost named[1611]: NSTATS 1161183746 1161180146 A=470 SOA=40 PTR=3 SRV=1
Oct 18 13:02:26 localhost named[1611]: XSTATS 1161183746 1161180146 RR=1012 RNXD=24 RFwdR=303 RDupR=0 RFail=0 RFErr=108 RErr=0
RAXFR=0 RLame=0 ROpts=0 SSysQ=165 SAns=466 SFwdQ=436 SDupQ=125 SErr=0 RQ=514 RIQ=0 RFwdQ=436 RDupQ=0 RTCP=0 SFwdR=303 SFail=5
SFErr=0 SNaAns=466 SNXD=81 RUQ=0 RURQ=0 RUXFR=0 RUUpd=0
Oct 18 13:17:01 localhost /USR/SBIN/CRON[2035]: (root) CMD ( run-parts --report /etc/cron.hourly)
Oct 18 13:41:44 localhost -- MARK --
Oct 18 14:01:44 localhost -- MARK --
Oct 18 14:02:26 localhost named[1611]: Cleaned cache of 279 RRsets
Oct 18 14:02:26 localhost named[1611]: USAGE 1161187346 1161180146 CPU=0.28u/0.1s CHILDCPU=0u/0s
Oct 18 14:02:26 localhost named[1611]: NSTATS 1161187346 1161180146 A=828 SOA=60 PTR=3 SRV=1
Oct 18 14:02:26 localhost named[1611]: XSTATS 1161187346 1161180146 RR=1691 RNXD=45 RFwdR=484 RDupR=16 RFail=0 RFErr=168 RErr=
0 RAXFR=0 RLame=0 ROpts=0 SSysQ=232 SAns=833 SFwdQ=791 SDupQ=208 SErr=0 RQ=892 RIQ=0 RFwdQ=791 RDupQ=0 RTCP=0 SFwdR=484 SFail=
5 SFErr=0 SNaAns=833 SNXD=121 RUQ=0 RURQ=0 RUXFR=0 RUUpd=0
Oct 18 14:13:30 localhost ddclient[1645]: WARNING: cannot connect to checkip.dyndns.org:80 socket: IO::Socket::INET: Bad host
name 'checkip.dyndns.org'
Oct 18 14:17:01 localhost /USR/SBIN/CRON[2040]: (root) CMD ( run-parts --report /etc/cron.hourly)
Oct 18 15:20:16 localhost syslogd 1.4.1#16: restart.
Oct 18 15:20:16 localhost kernel: klogd 1.4.1#16, log source = /proc/kmsg started.
Oct 18 15:20:16 localhost kernel: Inspecting /boot/System.map-2.4.27-2-386
Oct 18 15:20:17 localhost kernel: Loaded 18322 symbols from /boot/System.map-2.4.27-2-386.
Oct 18 15:20:17 localhost kernel: Symbols match kernel version 2.4.27.
Oct 18 15:20:17 localhost kernel: Loaded 636 symbols from 23 modules.
Oct 18 15:20:17 localhost kernel: Linux version 2.4.27-2-386 ([email protected]) (gcc version 3.3.5 (Debian 1:
3.3.5-6)) #1 Thu Jan 20 10:55:08 JST 2005
Oct 18 15:20:17 localhost kernel: BIOS-provided physical RAM map:
Oct 18 15:20:17 localhost kernel: BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)

muito obrigado pela atenção.

Boa tarde a todos.