Networking

PIX 防火牆導致丟包

  • July 28, 2012

我目前正在修改網際網路如何到達我的前端伺服器,並且我在現有堆棧之一中遇到了一個奇怪的問題。

伺服器上方有一個物理防火牆,如果我使用它,我會開始接收整個子網的丟包,如果我使用wireshark,我可以看到arp請求,但我仍然會丟包。第二次我把這個防火牆拿出來,問題就消失了。如果我繞過防火牆直接路由到前端伺服器,我仍然沒有遇到任何問題。

所有這一切讓我相信我的配置一定有問題,但我看不到我的生活會發生什麼:

interface ethernet0 100full
interface ethernet1 100full
interface ethernet2 auto shutdown
nameif ethernet0 outside security0
nameif ethernet1 inside security100
nameif ethernet2 intf2 security4
enable password ************ encrypted
passwd ************ encrypted
hostname sbc-cfw-02
fixup protocol dns maximum-length 512
no fixup protocol ftp 21
no fixup protocol h323 h225 1720
no fixup protocol h323 ras 1718-1719
fixup protocol http 80
no fixup protocol rsh 514
no fixup protocol rtsp 554
no fixup protocol sip 5060
no fixup protocol sip udp 5060
no fixup protocol skinny 2000
no fixup protocol smtp 25
no fixup protocol sqlnet 1521
fixup protocol tftp 69
names
name 10.17.2.0 as-net
name 10.17.2.1 sbc-fw-02-E1
name 10.17.2.2 sbc-as-01-E0
name 10.150.0.0 fe-net
name 10.150.0.221 sbc-fe-01-E1
name 10.150.0.222 sbc-fw-02-E0
name 10.150.0.223 sbc-as-01-nat
object-group service webstuff tcp
 port-object eq www
 port-object eq https
 port-object eq 8888
access-list inside_access_in permit icmp any any
access-list inside_access_in permit ip any any
access-list inside_access_in permit tcp any any
access-list inside_access_in permit udp any any
access-list inside_access_in permit tcp any host sbc-as-01-nat
access-list acl-web permit icmp any any
access-list acl-web permit tcp any any
access-list acl-web permit tcp any any object-group webstuff
access-list acl-web permit tcp any host sbc-as-01-nat eq ssh
pager lines 24
icmp permit any outside
icmp permit any inside
mtu outside 1500
mtu inside 1500
mtu intf2 1500
ip address outside sbc-fw-02-E0 255.255.255.0
ip address inside sbc-fw-02-E1 255.255.255.0
no ip address intf2
ip audit info action alarm
ip audit attack action alarm
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 10.150.0.1-10.150.0.210
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
static (inside,outside) sbc-as-01-nat sbc-as-01-E0 netmask 255.255.255.255 0 0
access-group acl-web in interface outside
access-group inside_access_in in interface inside
route outside 0.0.0.0 0.0.0.0 10.150.0.27 1
route outside 10.0.0.0 255.255.255.0 10.150.0.12 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout sip-disconnect 0:02:00 sip-invite 0:03:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server TACACS+ max-failed-attempts 3
aaa-server TACACS+ deadtime 10
aaa-server RADIUS protocol radius
aaa-server RADIUS max-failed-attempts 3
aaa-server RADIUS deadtime 10
aaa-server LOCAL protocol local
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
telnet timeout 5
ssh timeout 5
console timeout 0
terminal width 80

前端網路伺服器 (sbc-as-01) 在 10.17.2.0 範圍內,而有問題的一方是 10.150.0.* 子網。

如果您需要更多資訊,請與我們聯繫!

很有可能您在這些連結中的一個(或兩個)上的速度/雙工設置不匹配……

interface ethernet0 100full
interface ethernet1 100full

幾乎所有乙太網介面都預設為自動協商。如果您在這些防火牆介面上配置了手動速度/雙工,則另一端的自動協商將失敗(通常回落到 100-half)。不匹配的雙工會導致衝突(從而導致封包遺失)。只需刪除 Cisco 上的手動速度/雙工設置…

現在沒有充分的理由對速度/雙工進行硬編碼。在 autoneg 的早期,它並沒有很好的標準化;然而,那些日子早已一去不復返了。

引用自:https://serverfault.com/questions/412050