Robert Collins wrote: [snip]
If everything is fine until the second CR, then you probably have a MTU issue. See man iptables and put a MSS clamp rule in as they describe.
Bingo!
Thanks so much Rob this was exactly the problem. :-)
For the curious, the relevant man iptables info is,
TCPMSS This target allows to alter the MSS value of TCP SYN packets, to con- trol the maximum size for that connection (usually limiting it to your outgoing interfaces MTU minus 40). Of course, it can only be used in conjunction with -p tcp. This target is used to overcome criminally braindead ISPs or servers which block ICMP Fragmentation Needed packets. The symptoms of this problem are that everything works fine from your Linux firewall/router, but machines behind it can never exchange large packets: 1) Web browsers connect, then hang with no data received. 2) Small mail works fine, but large emails hang. 3) ssh works fine, but scp hangs after initial handshaking. Workaround: activate this option and add a rule to your firewall con- figuration like: iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN \ -j TCPMSS --clamp-mss-to-pmtu
Cheers
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