Trouble setting up hierarchy of caches

Hi,

I'm having problems setting up the following cache topology

                        +-----------+
                        | Parent 2 |
                        | Squid |
                        +-----------+
                              |
                              | <---- Firewall here
                              |
                        +-----------+
                        | Parent 1 |
                        | Harvest |
                        +-----------+
                              |
                              |
                              |
                      +----------------+
                      | Local |
                      | Squid beta 17 |
                      +----------------+

The firewall only allows traffic from Parent 1 to get through to
Parent 2 and this is working, and has been for 6 months.

I'd like to install a local cache, 'Local' on the picture, so that
every request that can't be satisfied locally is sent to Parent 1,
and if Parent 1 hasn't cached the page then it's sent to Parent 2 to
be fetched.

In the squid.conf file for 'Local' I've got a line that says
        cache_host parent1.my.domain parent 8080 3130
Parent 1 is setup to listen to these ports.

Am I totally missing something here or should all(most) requests that
can't be satisfied locally be sent to Parent 1?
I haven't changed any of the ACL stuff, is my problem in this area?

A copy of the relevant part of my cache.conf file is appended.

Many thanks
Gavin

 commHandleRead: FD 15: read 207 bytes
 asciiProcessInput: FD 15: reading request...
 asciiProcessInput: size = 207
 parseHttpRequest: Method is 'GET'
 parseHttpRequest: Request is 'http://www.unimelb.edu.au/'
 parseHttpRequest: HTTP version is 'HTTP/1.0'
 parseHttpRequest: Request Header is

---
Proxy-Connection: Keep-Alive
User-Agent: Mozilla/3.0b4Gold (Win95; I)
Host: www.unimelb.edu.au
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*
---
 parseHttpRequest: Complete request received
 aclCheck: cli_addr=203.17.189.130
 aclCheck: method=1
 aclCheck: proto=1
 aclCheck: host=www.unimelb.edu.au
 aclCheck: port=80
 aclCheck: request=/
 aclCheck: checking 'http_access deny manager !localhost'
 aclMatchAclList: list=0xa20d0  op=1
 aclMatchAcl: checking 'acl manager proto cache_object'
 aclMatchAclList: returning 0
 aclCheck: checking 'http_access deny CONNECT !SSL_ports'
 aclMatchAclList: list=0xa20f0  op=1
 aclMatchAcl: checking 'acl CONNECT method CONNECT'
 aclMatchAclList: returning 0
 aclCheck: checking 'http_access allow  all'
 aclMatchAclList: list=0xa2110  op=1
 aclMatchAcl: checking 'acl all src 0.0.0.0/0.0.0.0'
 aclMatchIp: h     = 0.0.0.0
 aclMatchIp: addr1 = 0.0.0.0
 aclMatchIp: addr2 = 0.0.0.0
 aclMatchIp: returning 1
 aclMatchAclList: returning 1
 aclCheck: match found, returning 1
 mime_get_header: looking for 'If-Modified-Since'
 mime_get_header: looking for 'Pragma'
 mime_get_header: looking for 'Authorization'
 icp_hit_or_miss: GET <URL:http://www.unimelb.edu.au/>
 icp_hit_or_miss: REQ_NOCACHE = NOT SET
 icp_hit_or_miss: REQ_CACHABLE = SET
 icp_hit_or_miss: REQ_HIERARCHICAL = SET
 storeGeneratePublicKey: type=1 http://www.unimelb.edu.au/
 storeGet: looking up http://www.unimelb.edu.au/
 icp_hit_or_miss: TCP_MISS for 'http://www.unimelb.edu.au/'
 icpProcessMISS: 'GET http://www.unimelb.edu.au/'
 storeCreateEntry: 'http://www.unimelb.edu.au/' icp flags=51
 new_MemObject: returning 0x12a080
 new_StoreEntry: returning 0xa3700
 storeGeneratePrivateKey: 'http://www.unimelb.edu.au/'
 storeHashInsert: Inserting Entry 0xa3700 key '1/GET/http://www.unimelb.edu.au/'
 new_MemObjectData: calling memInit()
 storeRegister: FD 15 '1/GET/http://www.unimelb.edu.au/'
 protoDispatch: GET URL: http://www.unimelb.edu.au/
 comm_add_close_handler: fd=15 handler=0x0x1e78c data=0x0xa37c0
 protoDispatch: inside_firewall = 2 (NO_FIREWALL)
 protoDispatch: query_neighbors = 8192
 protoDispatch:         n_edges = 1
 protoDispatch:   single_parent = www-proxy.ormond.unimelb.edu.au
 ipcache_nbgethostbyname: FD 15: Name 'www.unimelb.edu.au'.
 ipcache_nbgethostbyname: MISS for 'www.unimelb.edu.au'
 ipcache_add_to_hash: name <www.unimelb.edu.au>
 comm_write: FD 4: sz 19: tout 0: hndl 0x0: data 0x0.
 dnsDispatch: Request sent to DNS server #1.
 Removed 0 expired objects
 comm_select: 1 sockets ready at 836745252
 comm_select: FD 4 ready for writing
 commHandleWrite: FD 4: state=0xa3840, off 0, sz 19.
 comm_select: 1 sockets ready at 836745252
 comm_select: FD 4 ready for reading
 ipcache_dnsHandleRead: Result from DNS ID 1 (100 bytes)
 comm_select: 1 sockets ready at 836745252
 comm_select: FD 4 ready for reading
 ipcache_dnsHandleRead: Result from DNS ID 1 (15 bytes)
 ipcache_parsebuffer: $name www.unimelb.edu.au
 ipcache_parsebuffer: $h_name miriworld.its.unimelb.EDU.AU
 ipcache_parsebuffer: $h_len 4
 ipcache_parsebuffer: $ipcount 1
 ipcache_parsebuffer: 128.250.6.194
 ipcache_parsebuffer: $aliascount 0
 neighborsUdpPing: Edge www-proxy.ormond.unimelb.edu.au
 neighborsUdpPing: pinging cache www-proxy.ormond.unimelb.edu.au for <URL:http://www.unimelb.edu.au/>
 neighborsUdpPing: key = '1/GET/http://www.unimelb.edu.au/'
 neighborsUdpPing: reqnum = 1
 icpUdpSend: headerp->reqnum = 16777216
 icpUdpSend: Queueing for 203.17.189.1: "ICP_QUERY http://www.unimelb.edu.au/"
 neighborsUdpPing: Source Ping is disabled.
 comm_select: 1 sockets ready at 836745252
 icpUdpReply: FD 17 sending 51 bytes to 203.17.189.1 port 3130
 comm_select: 1 sockets ready at 836745252
 icpHandleUdp: FD 17: received 47 bytes from 203.17.189.1.
 icpHandleUdp: Neighbor 203.17.189.1 returned reqnum = 0
 icpHandleUdp: Disabling use of private keys
 icpHandleUdp: ICP_HIT from 203.17.189.1 for 'http://www.unimelb.edu.au/'
 storeGeneratePublicKey: type=1 http://www.unimelb.edu.au/
 icpHandleUdp: Looking for key 'http://www.unimelb.edu.au/'
 storeGet: looking up http://www.unimelb.edu.au/
 icpHandleUdp: Ignoring ICP_HIT for NULL Entry.
 comm_select: 0 sockets ready at 836745252
 comm_select: 0 sockets ready at 836745253
 comm_select: 0 sockets ready at 836745254
 comm_select: timeout on socket 15 at 836745254
 getFromDefaultSource: Timeout occured pinging for <URL:http://www.unimelb.edu.au/>
 getFromCache: FD 15 <URL:http://www.unimelb.edu.au/>
 getFromCache: --> type = GET
 getFromCache: --> getting from 'source'
 protoCancelTimeout: FD 15 <URL:http://www.unimelb.edu.au/>
 httpStart: "GET http://www.unimelb.edu.au/"
 storeLockObject: locks 2: '1/GET/http://www.unimelb.edu.au/'
 comm_add_close_handler: fd=18 handler=0x0x10f00 data=0x0xa3880
 comm_set_fd_lifetime: FD 18 lft 120