Hi
Since its a secure site to site VPN connection between your HO and Italy remote office then ISP cannot block the http traffic. I would suspect the mtu related problem. Is there any other web servcies are working fine from Italy office to HO? Kindly do the below:
- To avoid the possible fragmentation through VPN, run the below command on HO and your remote offices SRX
set security flow tcp-mss ipsec-vpn mss 1350
- If problem persist then Enable the traceoption for the traffic on London and Italy office SRX and post the output of show logs log-file
set security flow traceoptions file log-file
set security flow traceoptions flag basic-datapath
set security flow traceoptions flag packet-drops
set security flow traceoptions packet-filter pac1 source-prefix <any source ip from the ITALY office>
set security flow traceoptions packet-filter pac1 destination-prefix <Web server ip on London HO>
set security flow traceoptions packet-filter pac2 source-prefix <Web server ip on London HO>
set security flow traceoptions packet-filter pac2 destination-prefix <any source ip from the ITALY office>
HTH