PIX Syn/Ack Issues

[MMIGuy]

Hello.

We recently changed ISPs and in taking advantage of the downtime, I decided to upgrade our PIX 5.2(1) to the latest version, 6.3(4). The configuration basically stayed the same with of course the appropriate changes in the commands.

What's basically happening now is that for some reason, some sites I basically am blocked from, for no apparent reason. But what's even stranger, is that on one of these sites, the https (443) is completely open, while nmap reports the rest as being filtered. If I try and telnet to port 80 on our external router, I can connect just fine, so it's something with the PIX.

I did some debugging to see if I could figure it out, and what's basically happening is that for port 80, I send a SYN packet, but only receive back an ACK, not an ACK/SYN. In turn, the client then sends back a RST and the handshake fails.

I've tried everything I can think of, including NAT vs. PAT (hence the 2 global entries.

Any help would be *greatly* appreciated as I have been on this for several weeks and people are starting to get aggrevated (to say the least =x)

Thanks,
Mike

fire# show conf
: Saved
: Written by enable_15 at 09:35:15.641 UTC Mon Apr 11 2005
PIX Version 6.3(4)
interface ethernet0 auto
interface ethernet1 auto
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password {xxxxx} encrypted
passwd {xxxxx} encrypted
hostname fire
domain-name ciscopix.com
fixup protocol dns maximum-length 512
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
no fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
names
access-list 102 permit ip 172.20.0.0 255.255.255.0 192.168.0.0 255.255.0.0
access-list 102 permit ip 192.168.0.0 255.255.255.0 172.20.0.0 255.255.0.0
access-list 102 permit ip 172.20.0.0 255.255.255.0 128.1.0.0 255.255.0.0
access-list acl_out permit icmp any any
access-list inbound permit icmp any any
access-list outside_acl permit icmp any any
access-list outside_acl permit tcp any host x.x.x.100 eq smtp
access-list outside_acl permit tcp any host x.x.x.100 eq www
access-list outside_acl permit tcp any host x.x.x.100 eq pop3
access-list outside_acl permit tcp any host x.x.x.101 eq smtp
access-list outside_acl permit tcp any host x.x.x.101 eq www
access-list outside_acl permit tcp any host x.x.x.102 eq smtp
access-list outside_acl permit tcp any host x.x.x.102 eq www
access-list outside_acl permit tcp any host x.x.x.102 eq pop3
access-list outside_acl permit tcp any host x.x.x.102 eq imap4
access-list outside_acl permit tcp any host x.x.x.102 eq ftp
access-list outside_acl permit tcp any host x.x.x.102 eq https
access-list outside_acl permit tcp any host x.x.x.109 eq 6080
access-list outside_acl permit tcp any host x.x.x.109 eq 9080
access-list PERMIT_ICMP permit udp any any eq snmp
pager lines 24
logging monitor warnings
mtu outside 1500
mtu inside 1500
ip address outside x.x.x.99 255.255.255.224
ip address inside 172.20.0.8 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
pdm history enable
arp timeout 14400
global (outside) 1 x.x.x.110-x.x.x.126 netmask 255.255.255.224
global (outside) 1 x.x.x.104
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
static (inside,outside) x.x.x.102 172.20.0.15 netmask 255.255.255.255 0 0
static (inside,outside) x.x.x.100 172.20.0.26 netmask 255.255.255.255 0 0
static (inside,outside) x.x.x.101 172.20.0.17 netmask 255.255.255.255 0 0
static (inside,outside) x.x.x.109 172.20.0.11 netmask 255.255.255.255 0 0
access-group outside_acl in interface outside
route outside 0.0.0.0 0.0.0.0 x.x.x.97 1
route inside 172.20.3.0 255.255.255.0 172.20.0.25 1
route inside 192.168.0.0 255.255.0.0 172.20.0.1 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 0:10:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
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
snmp-server host inside 172.20.0.18 poll
snmp-server host inside 172.20.0.20 poll
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
sysopt connection permit-ipsec
telnet 172.20.0.0 255.255.255.0 inside
telnet timeout 60
ssh 172.20.0.0 255.255.255.0 inside
ssh timeout 40
console timeout 0
terminal width 80
Cryptochecksum:b9ef9aff0c4876b5508488458a81d64d

 

[rtfmdude]

no fixup protocol http?

 

[MMIGuy]

Yeah, I already tried that and it looks like it didn't do anything. I've narrowed down to one site that I'm having issues with and in talking with their administrators over there, they say that nothing is different from https compared to http, which is why this is so odd.

-Mike