The current /etc/services contains a double entry for webcache for port 3128 and 8080. This prevents the usage of the service name in iptables (and may address the wrong port).
you're using an old baselayout, that has been resolved a while ago
I use the latest unasked: bash-2.05b# etcat -v baselayout [ Results for search key : baselayout ] [ Candidate applications found : 8 ] Only printing found installed programs. * sys-apps/baselayout : [ ] 1.9.4-r3 (0) OVERLAY [M ] 1.9.4-r4 (0) OVERLAY [ ] 1.9.4-r5 (0) OVERLAY [ I] 1.9.4-r6 (0) OVERLAY [M~ ] 1.10.3 (0) OVERLAY [M~ ] 1.10.4 (0) OVERLAY [M~ ] 1.11.5 (0) OVERLAY [M~ ] 1.11.6-r1 (0) OVERLAY