PIX 501 blocking inside to out arp requests

Discussion in 'Cisco' started by Tyler, May 20, 2008.

  1. Tyler

    Tyler Guest

    Hello.

    I've got a Cisco PIX 501 that I like to use as my boarder firewall/
    router for my home. However, I have found one situation where I have
    to swap the 501 for a dumb Linksys router/NAT device.

    I work from home as a software consultant, and one of the clients I
    work for has a VPN concentrator that I can not connect to with my PIX
    inline.

    I think I have narrowed it down to the VPN Adapter that is created
    when I connect to their concentrator.

    Ethernet adapter Cisco Systems VPN Adapter:

    Connection-specific DNS Suffix . : XXXX.XXX
    Description . . . . . . . . . . . : Cisco Systems VPN Adapter
    Physical Address. . . . . . . . . : 00-05-9A-3C-78-00
    Dhcp Enabled. . . . . . . . . . . : No
    IP Address. . . . . . . . . . . . : 192.168.16.2
    Subnet Mask . . . . . . . . . . . : 255.255.255.224
    Default Gateway . . . . . . . . . :
    DNS Servers . . . . . . . . . . . : 192.168.1.10

    There is no 'Default Gateway'. With the PIX in line I can not connect
    to their server 192.168.15.2, etc.. With the Linksys in line every
    thing seems to work fine.

    I have tried to contact their network admin to resolve the issue, but
    they have been very un-responsive. Is there any setting I can change
    on my PIX?

    I'm guessing (as I'm no network guru) that the Linksys router is
    allowing ARP requests to traverse the device, and the PIX is blocking
    them since there is now pre-defined route, or maybe this guess is way
    off, I don't really know.

    Any help would greatly be appreciated.

    -Tyler
    Tyler, May 20, 2008
    #1
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  2. Tyler <> writes:
    >I've got a Cisco PIX 501 that I like to use as my boarder firewall/
    >router for my home. However, I have found one situation where I have
    >to swap the 501 for a dumb Linksys router/NAT device.


    >I work from home as a software consultant, and one of the clients I
    >work for has a VPN concentrator that I can not connect to with my PIX
    >inline.


    >I think I have narrowed it down to the VPN Adapter that is created
    >when I connect to their concentrator.


    Probably not..

    >There is no 'Default Gateway'. With the PIX in line I can not connect
    >to their server 192.168.15.2, etc.. With the Linksys in line every
    >thing seems to work fine.


    Do you have the PIX configured to let IPsec packets through?

    sysopt connection permit-ipsec

    I'm assuming you are already doing NAT-T on your VPN setup since you
    say the Linksys one works.

    >I'm guessing (as I'm no network guru) that the Linksys router is
    >allowing ARP requests to traverse the device, and the PIX is blocking
    >them since there is now pre-defined route, or maybe this guess is way
    >off, I don't really know.


    Yes, this guess is way off..
    Doug McIntyre, May 20, 2008
    #2
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  3. Tyler

    Tyler Guest

    > Do you have the PIX configured to let IPsec packets through?
    >
    > sysopt connection permit-ipsec
    >


    I did not have this statement in my config.

    However, other sites that I VPN to worked fine, all "seem" to be
    configured using IPSec over UDP (NAT / PAT) in the Cisco VPN Client
    I'm using to connect to the client through my PIX / Linksys router.

    I have added the statement to my PIX, but I haven't had a chance to
    test it yet as the PIX is currently not hooked up. I'll give it a
    test later today when I disconnect from the client I'm working with.

    > I'm assuming you are already doing NAT-T on your VPN setup since you
    > say the Linksys one works.
    >
    > >I'm guessing (as I'm no network guru) that the Linksys router is
    > >allowing ARP requests to traverse the device, and the PIX is blocking
    > >them since there is now pre-defined route, or maybe this guess is way
    > >off, I don't really know.

    >
    > Yes, this guess is way off..


    Thanks
    Tyler, May 20, 2008
    #3
  4. Tyler

    Tyler Guest

    I have put the PIX back in place and added:

    sysopt connection permit-ipsec
    sysopt connection permit-pptp
    sysopt connection permit-l2tp

    One at a time testing each seperately, none of them made any
    difference to the connection, I am still unable to ping the address at
    the other end of the tunnel as when I have my Linksys Router in place.

    Here is my entire config:

    PIX Version 6.3(5)
    interface ethernet0 100full
    interface ethernet1 100full
    nameif ethernet0 outside security0
    nameif ethernet1 inside security100
    enable password xx
    passwd xx
    hostname pix
    domain-name xxxxxx
    clock timezone EST -5
    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
    no fixup protocol sip 5060
    no fixup protocol sip udp 5060
    fixup protocol skinny 2000
    fixup protocol smtp 25
    fixup protocol sqlnet 1521
    fixup protocol tftp 69
    no names
    access-list inbound permit tcp any any eq ssh
    access-list inbound permit icmp any any
    access-list inbound permit tcp any any eq smtp
    access-list inbound permit tcp any any eq domain
    access-list inbound permit udp any any eq domain
    access-list inbound permit tcp host x.x.x.x any eq www
    access-list inbound permit tcp host x.x.x.x any eq 1984
    access-list inbound permit tcp host x.x.x.x any eq 1984
    access-list outbound permit tcp host 192.168.1.7 any eq smtp
    access-list outbound deny tcp any any eq smtp
    access-list outbound permit ip any any
    pager lines 255
    logging on
    logging timestamp
    logging standby
    logging monitor alerts
    logging trap informational
    logging history debugging
    logging facility 19
    logging host inside 192.168.1.5
    mtu outside 1500
    mtu inside 1500
    ip address outside x.x.x.x 255.255.255.252
    ip address inside 192.168.1.1 255.255.255.0
    ip audit info action alarm
    ip audit attack action alarm
    no pdm history enable
    arp timeout 14400
    global (outside) 1 interface
    nat (inside) 1 192.168.1.0 255.255.255.0 0 0
    static (inside,outside) tcp interface ssh 192.168.1.7 ssh netmask
    255.255.255.255 0 0
    static (inside,outside) tcp interface smtp 192.168.1.7 smtp netmask
    255.255.255.255 0 0
    static (inside,outside) tcp interface domain 192.168.1.7 domain
    netmask 255.255.255.255 0 0
    static (inside,outside) udp interface domain 192.168.1.7 domain
    netmask 255.255.255.255 0 0
    static (inside,outside) tcp interface www 192.168.1.7 www netmask
    255.255.255.255 0 0
    static (inside,outside) tcp interface 1984 192.168.1.7 1984 netmask
    255.255.255.255 0 0
    access-group inbound in interface outside
    access-group outbound in interface inside
    route outside 0.0.0.0 0.0.0.0 x.x.x.x 1
    timeout xlate 0:05:00
    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
    aaa authentication http console LOCAL
    aaa authentication ssh console LOCAL
    ntp server x.x.x.x source outside
    no snmp-server location
    no snmp-server contact
    snmp-server community public
    no snmp-server enable traps
    floodguard enable
    sysopt connection timewait
    sysopt connection permit-ipsec
    sysopt connection permit-pptp
    sysopt connection permit-l2tp
    isakmp enable inside
    isakmp nat-traversal 3600
    telnet timeout 5
    ssh 192.168.1.0 255.255.255.0 inside
    ssh timeout 60
    console timeout 0
    username XX xx
    terminal width 80
    Tyler, May 20, 2008
    #4
  5. Tyler

    Tyler Guest

    Any other ideas?
    Tyler, May 22, 2008
    #5
  6. Tyler kirjoitti:
    > Any other ideas?


    I the dns server 192.168.1.10 in your network or across the VPN? This
    could be the problem. Can you connect using IP addresses only

    Regards

    Marko
    Marko Uusitalo, May 22, 2008
    #6
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